Deployment dynamics of a simplified spinning IKAROS solar sail via absolute coordinate based method
NASA Astrophysics Data System (ADS)
Zhao, Jiang; Tian, Qiang; Hu, Hai-Yan
2013-02-01
The spinning solar sail of large scale has been well developed in recent years. Such a solar sail can be considered as a rigid-flexible multibody system mainly composed of a spinning central rigid hub, a number of flexible thin tethers, sail membranes, and tip masses. A simplified interplanetary kite-craft accelerated by radiation of the Sun (IKAROS) model is established in this study by using the absolute-coordinate-based (ACB) method that combines the natural coordinate formulation (NCF) describing the central rigid hub and the absolute nodal coordinate formulation (ANCF) describing flexible parts. The initial configuration of the system in the second-stage deployment is determined through both dynamic and static analyses. The huge set of stiff equations of system dynamics is solved by using the generalized-alpha method, and thus the deployment dynamics of the system can be well understood.
An Approach to Absolute Position Control based on Object Coordinate
NASA Astrophysics Data System (ADS)
Nakano, Keisuke; Murakami, Toshiyuki
This paper describes an accurate position control in object coordinate. In case the motion control of industrial robot placed in global coordinate is considered in object coordinate, it is preferable and convenient to decide its motion by the teaching of robot operator. However the teaching procedure requires much time and effort. Moreover, as often as relative position between robot and object is changed, the operator needs to do the teaching operation again. To improve the above issue, it is required to develop the strategy that decides the robot motion without the teaching operation. This paper proposes a control strategy that is not required the teaching operation and enables to realize the desired motion without affecting the relative position error between the robot and the target object in object coordinate defined by PSD (Position Sensitive Detector). In the proposed approach, the estimation algorithm of the kinetic transformation between global and object coordinates is introduced by using PSD output, and the error of coordinate transformation estimated by the proposed approach is compensated in global coordinate. The validity of the proposed method is shown by simulations and experiments.
Monolithically integrated absolute frequency comb laser system
Wanke, Michael C.
2016-07-12
Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.
Absolute flatness testing of skip-flat interferometry by matrix analysis in polar coordinates.
Han, Zhi-Gang; Yin, Lu; Chen, Lei; Zhu, Ri-Hong
2016-03-20
A new method utilizing matrix analysis in polar coordinates has been presented for absolute testing of skip-flat interferometry. The retrieval of the absolute profile mainly includes three steps: (1) transform the wavefront maps of the two cavity measurements into data in polar coordinates; (2) retrieve the profile of the reflective flat in polar coordinates by matrix analysis; and (3) transform the profile of the reflective flat back into data in Cartesian coordinates and retrieve the profile of the sample. Simulation of synthetic surface data has been provided, showing the capability of the approach to achieve an accuracy of the order of 0.01 nm RMS. The absolute profile can be retrieved by a set of closed mathematical formulas without polynomial fitting of wavefront maps or the iterative evaluation of an error function, making the new method more efficient for absolute testing. PMID:27140578
Absolute calibration in vivo measurement systems
Kruchten, D.A.; Hickman, D.P.
1991-02-01
Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs.
NASA Astrophysics Data System (ADS)
Laundal, K. M.; Richmond, A. D.
2016-07-01
Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.
Contact dynamics of elasto-plastic thin beams simulated via absolute nodal coordinate formulation
NASA Astrophysics Data System (ADS)
Wang, Qing-Tao; Tian, Qiang; Hu, Hai-Yan
2015-12-01
Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation (ANCF). The internal force of the elasto-plastic spatial thin beam element is derived under the assumption that the plastic strain of the beam element depends only on its longitudinal deformation. A new body-fixed local coordinate system is introduced into the spatial thin beam element of ANCF for efficient contact detection in the contact dynamics simulation. The linear isotropic hardening constitutive law is used to describe the elasto-plastic deformation of beam material, and the classical return mapping algorithm is adopted to evaluate the plastic strains. A multi-zone contact approach of thin beams previously proposed by the authors is also introduced to detect the multiple contact zones of beams accurately, and the penalty method is used to compute the normal contact force of thin beams in contact. Four numerical examples are given to demonstrate the applicability and effectiveness of the proposed elasto-plastic spatial thin beam element of ANCF for flexible multibody system dynamics.
Contact dynamics of elasto-plastic thin beams simulated via absolute nodal coordinate formulation
NASA Astrophysics Data System (ADS)
Wang, Qing-Tao; Tian, Qiang; Hu, Hai-Yan
2016-06-01
Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation (ANCF). The internal force of the elasto-plastic spatial thin beam element is derived under the assumption that the plastic strain of the beam element depends only on its longitudinal deformation. A new body-fixed local coordinate system is introduced into the spatial thin beam element of ANCF for efficient contact detection in the contact dynamics simulation. The linear isotropic hardening constitutive law is used to describe the elasto-plastic deformation of beam material, and the classical return mapping algorithm is adopted to evaluate the plastic strains. A multi-zone contact approach of thin beams previously proposed by the authors is also introduced to detect the multiple contact zones of beams accurately, and the penalty method is used to compute the normal contact force of thin beams in contact. Four numerical examples are given to demonstrate the applicability and effectiveness of the proposed elasto-plastic spatial thin beam element of ANCF for flexible multibody system dynamics.
NASA Astrophysics Data System (ADS)
Duke, Dennis W.
2002-07-01
In his "Histoire de l'Astronomie Ancienne" Delambre concludes unequivocally that Hipparchus knew and used a definite system of celestial spherical coordinates, namely the right ascension and declination system that we use today. The basis of Delambre's conclusion was disarmingly simple: he pointed out that in the "Commentary to Aratus" Hipparchus actually quotes the positions of numerous stars directly in right ascension and declination (or more often its complement, polar distance). Nearly two centuries later, in his "A History of Ancient Mathematical Astronomy", Neugebauer not only completely ignores Delambre's conclusion on this issue, but goes further to propose his own, as we shall see quite fanciful, theory that begins "From the Commentary to Aratus, it is quite obvious that at Hipparchus' time a definite system of spherical coordinates for stellar positions did not yet exist." and concludes "...nowhere in Greek astronomy before the catalogue of stars in the Almagest is it attested that orthogonal spherical coordinates are used to determine stellar positions." Today it is clear that Neugebauer's theory is conventionally accepted. It is the purpose of this paper to offer fresh arguments that Delambre was correct.
Multipole Structure and Coordinate Systems
ERIC Educational Resources Information Center
Burko, Lior M.
2007-01-01
Multipole expansions depend on the coordinate system, so that coefficients of multipole moments can be set equal to zero by an appropriate choice of coordinates. Therefore, it is meaningless to say that a physical system has a nonvanishing quadrupole moment, say, without specifying which coordinate system is used. (Except if this moment is the…
Burgett, S.; Meindl, M.
1994-09-01
It is useful in a variety of military and commercial application to accurately register the position of synthetic aperture radar (SAR) imagery in absolute coordinates. The two basic SAR measurements, range and doppler, can be used to solve for the position of the SAR image. Imprecise knowledge of the SAR collection platform`s position and velocity vectors introduce errors in the range and doppler measurements and can cause the apparent location of the SAR image on the ground to be in error by tens of meters. Recent advances in carrier phase GPS techniques can provide an accurate description of the collection vehicle`s trajectory during the image formation process. In this paper, highly accurate carrier phase GPS trajectory information is used in conjunction with SAR imagery to demonstrate a technique for accurate registration of SAR images in WGS-84 coordinates. Flight test data will be presented that demonstrates SAR image registration errors of less than 4 meters.
Compact-range coordinate system established using a laser tracker.
Gallegos, Floyd H.; Bryce, Edwin Anthony
2006-12-01
Establishing a Cartesian coordinate reference system for an existing Compact Antenna Range using the parabolic reflector is presented. A SMX (Spatial Metrix Corporation) M/N 4000 laser-based coordinate measuring system established absolute coordinates for the facility. Electric field characteristics with positional movement correction are evaluated. Feed Horn relocation for alignment with the reflector axis is also described. Reference points are established for follow-on non-laser alignments utilizing a theodolite.
Karst Water System Investigated by Absolute Gravimetry
NASA Astrophysics Data System (ADS)
Quinif, Y.; Meus, P.; van Camp, M.; Kaufmann, O.; van Ruymbeke, M.; Vandiepenbeeck, M.; Camelbeeck, T.
2006-12-01
The highly anisotropic and heterogeneous hydrogeological characteristics of karst aquifers are difficult to characterize and present challenges for modeling of storage capacities. Little is known about the surface and groundwater interconnection, about the connection between the porous formations and the draining cave and conduits, and about the variability of groundwater volume within the system. Usually, an aquifer is considered as a black box, where water fluxes are monitored as input and output. However, water inflow and outflow are highly variable and cannot be measured directly. A recent project, begun in 2006 sought to constrain the water budget in a Belgian karst aquifer and to assess the porosity and water dynamics, combining absolute gravity (AG) measurements and piezometric levels around the Rochefort cave. The advantage of gravity measurements is that they integrate all the subsystems in the karst system. This is not the case with traditional geophysical tools like boring or monitoring wells, which are soundings affected by their near environment and its heterogeneity. The investigated cave results from the meander cutoff system of the Lomme River. The main inputs are swallow holes of the river crossing the limestone massif. The river is canalized and the karst system is partly disconnected from the hydraulic system. In February and March 2006, when the river spilled over its dyke and sank into the most important swallow hole, this resulted in dramatic and nearly instantaneous increases in the piezometric levels in the cave, reaching up to 13 meters. Meanwhile, gravity increased by 50 and 90 nms-2 in February and March, respectively. A first conclusion is that during these sudden floods, the pores and fine fissures were poorly connected with the enlarged fractures, cave, and conduits. With a rise of 13 meters in the water level and a 5% porosity, a gravity change of 250 nms-2 should have been expected. This moderate gravity variation suggests either a
Absolute radiometric calibration of advanced remote sensing systems
NASA Technical Reports Server (NTRS)
Slater, P. N.
1982-01-01
The distinction between the uses of relative and absolute spectroradiometric calibration of remote sensing systems is discussed. The advantages of detector-based absolute calibration are described, and the categories of relative and absolute system calibrations are listed. The limitations and problems associated with three common methods used for the absolute calibration of remote sensing systems are addressed. Two methods are proposed for the in-flight absolute calibration of advanced multispectral linear array systems. One makes use of a sun-illuminated panel in front of the sensor, the radiance of which is monitored by a spectrally flat pyroelectric radiometer. The other uses a large, uniform, high-radiance reference ground surface. The ground and atmospheric measurements required as input to a radiative transfer program to predict the radiance level at the entrance pupil of the orbital sensor are discussed, and the ground instrumentation is described.
NASA Astrophysics Data System (ADS)
Gerstmayr, Johannes; Irschik, Hans
2008-12-01
In finite element methods that are based on position and slope coordinates, a representation of axial and bending deformation by means of an elastic line approach has become popular. Such beam and plate formulations based on the so-called absolute nodal coordinate formulation have not yet been verified sufficiently enough with respect to analytical results or classical nonlinear rod theories. Examining the existing planar absolute nodal coordinate element, which uses a curvature proportional bending strain expression, it turns out that the deformation does not fully agree with the solution of the geometrically exact theory and, even more serious, the normal force is incorrect. A correction based on the classical ideas of the extensible elastica and geometrically exact theories is applied and a consistent strain energy and bending moment relations are derived. The strain energy of the solid finite element formulation of the absolute nodal coordinate beam is based on the St. Venant-Kirchhoff material: therefore, the strain energy is derived for the latter case and compared to classical nonlinear rod theories. The error in the original absolute nodal coordinate formulation is documented by numerical examples. The numerical example of a large deformation cantilever beam shows that the normal force is incorrect when using the previous approach, while a perfect agreement between the absolute nodal coordinate formulation and the extensible elastica can be gained when applying the proposed modifications. The numerical examples show a very good agreement of reference analytical and numerical solutions with the solutions of the proposed beam formulation for the case of large deformation pre-curved static and dynamic problems, including buckling and eigenvalue analysis. The resulting beam formulation does not employ rotational degrees of freedom and therefore has advantages compared to classical beam elements regarding energy-momentum conservation.
Terrestrial Coordinate Systems and Frames
NASA Astrophysics Data System (ADS)
Boucher, C.; Murdin, P.
2000-11-01
A terrestrial reference system (TRS) is a spatial reference system corotating with the Earth in its DIURNAL MOTION in space. In such a system, the positions of points anchored on the Earth's solid surface have coordinates which have only small variations with time, as a result of geophysical effects (tectonic or tidal deformations; see TECTONICS, EARTH'S INTERIOR, TIDES). A terrestrial reference ...
Orion Absolute Navigation System Progress and Challenge
NASA Technical Reports Server (NTRS)
Holt, Greg N.; D'Souza, Christopher
2012-01-01
The absolute navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.
Simple and accurate empirical absolute volume calibration of a multi-sensor fringe projection system
NASA Astrophysics Data System (ADS)
Gdeisat, Munther; Qudeisat, Mohammad; AlSa`d, Mohammed; Burton, David; Lilley, Francis; Ammous, Marwan M. M.
2016-05-01
This paper suggests a novel absolute empirical calibration method for a multi-sensor fringe projection system. The optical setup of the projector-camera sensor can be arbitrary. The term absolute calibration here means that the centre of the three dimensional coordinates in the resultant calibrated volume coincides with a preset centre to the three-dimensional real-world coordinate system. The use of a zero-phase fringe marking spot is proposed to increase depth calibration accuracy, where the spot centre is determined with sub-pixel accuracy. Also, a new method is proposed for transversal calibration. Depth and transversal calibration methods have been tested using both single sensor and three-sensor fringe projection systems. The standard deviation of the error produced by this system is 0.25 mm. The calibrated volume produced by this method is 400 mm×400 mm×140 mm.
Orion Absolute Navigation System Progress and Challenges
NASA Technical Reports Server (NTRS)
Holt, Greg N.; D'Souza, Christopher
2011-01-01
The Orion spacecraft is being designed as NASA's next-generation exploration vehicle for crewed missions beyond Low-Earth Orbit. The navigation system for the Orion spacecraft is being designed in a Multi-Organizational Design Environment (MODE) team including contractor and NASA personnel. The system uses an Extended Kalman Filter to process measurements and determine the state. The design of the navigation system has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudorange and deltarange, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, pad alignment, cold start are discussed as are
Global absolut gravity reference system as replacement of IGSN 71
NASA Astrophysics Data System (ADS)
Wilmes, Herbert; Wziontek, Hartmut; Falk, Reinhard
2015-04-01
The determination of precise gravity field parameters is of great importance in a period in which earth sciences are achieving the necessary accuracy to monitor and document global change processes. This is the reason why experts from geodesy and metrology joined in a successful cooperation to make absolute gravity observations traceable to SI quantities, to improve the metrological kilogram definition and to monitor mass movements and smallest height changes for geodetic and geophysical applications. The international gravity datum is still defined by the International Gravity Standardization Net adopted in 1971 (IGSN 71). The network is based upon pendulum and spring gravimeter observations taken in the 1950s and 60s supported by the early free fall absolute gravimeters. Its gravity values agreed in every case to better than 0.1 mGal. Today, more than 100 absolute gravimeters are in use worldwide. The series of repeated international comparisons confirms the traceability of absolute gravity measurements to SI quantities and confirm the degree of equivalence of the gravimeters in the order of a few µGal. For applications in geosciences where e.g. gravity changes over time need to be analyzed, the temporal stability of an absolute gravimeter is most important. Therefore, the proposition is made to replace the IGSN 71 by an up-to-date gravity reference system which is based upon repeated absolute gravimeter comparisons and a global network of well controlled gravity reference stations.
Computer aided coordinate measuring systems
NASA Astrophysics Data System (ADS)
Nastri, J. W.
Sikorsky's computer-aided inspection system and equipment utilized to assure that manufactured parts meet drawing tolerance specifications are discussed. An overview of the system is given, and the software is described, including the monitor console routine and commands and the language commands. The system's three coordinate measuring machines are discussed, and the part inspection methods are described in stepwise fashion. System benefits and time savings items are detailed, including quick and accurate measurement of parts difficult to inspect by conventional methods, significant reduction in inspection time, a consistent baseline that highlights variances, and the use of personnel with lower skill levels to effectively inspect critical parts.
System and method for calibrating a rotary absolute position sensor
NASA Technical Reports Server (NTRS)
Davis, Donald R. (Inventor); Permenter, Frank Noble (Inventor); Radford, Nicolaus A (Inventor)
2012-01-01
A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device.
Estimation of the absolute position of mobile systems by an optoelectronic processor
NASA Technical Reports Server (NTRS)
Feng, Liqiang; Fainman, Yeshaiahu; Koren, Yoram
1992-01-01
A method that determine the absolute position of a mobile system with a hybrid optoelectronic processor has been developed. Position estimates are based on an analysis of circular landmarks that are detected by a TV camera attached to the mobile system. The difference between the known shape of the landmark and its image provides the information needed to determine the absolute position of the mobile system. For robust operation, the parameters of the landmark image are extracted at high speeds using an optical processor that performs an optical Hough transform. The coordinates of the mobile system are computed from these parameters in a digital co-processor using fast algorithms. Different sources of position estimation errors have also been analyzed, and consequent algorithms to improve the navigation performance of the mobile system have been developed and evaluated by both computer simulation and experiments.
Mathematical Model for Absolute Magnetic Measuring Systems in Industrial Applications
NASA Astrophysics Data System (ADS)
Fügenschuh, Armin; Fügenschuh, Marzena; Ludszuweit, Marina; Mojsic, Aleksandar; Sokół, Joanna
2015-09-01
Scales for measuring systems are either based on incremental or absolute measuring methods. Incremental scales need to initialize a measurement cycle at a reference point. From there, the position is computed by counting increments of a periodic graduation. Absolute methods do not need reference points, since the position can be read directly from the scale. The positions on the complete scales are encoded using two incremental tracks with different graduation. We present a new method for absolute measuring using only one track for position encoding up to micrometre range. Instead of the common perpendicular magnetic areas, we use a pattern of trapezoidal magnetic areas, to store more complex information. For positioning, we use the magnetic field where every position is characterized by a set of values measured by a hall sensor array. We implement a method for reconstruction of absolute positions from the set of unique measured values. We compare two patterns with respect to uniqueness, accuracy, stability and robustness of positioning. We discuss how stability and robustness are influenced by different errors during the measurement in real applications and how those errors can be compensated.
Zhang Song; Yau Shingtung
2008-06-10
For a three-dimensional shape measurement system with a single projector and multiple cameras, registering patches from different cameras is crucial. Registration usually involves a complicated and time-consuming procedure. We propose a new method that can robustly match different patches via absolute phase without significantly increasing its cost. For y and z coordinates, the transformations from one camera to the other are approximated as third-order polynomial functions of the absolute phase. The x coordinates involve only translations and scalings. These functions are calibrated and only need to be determined once. Experiments demonstrated that the alignment error is within RMS 0.7 mm.
Absolute calibration of vacuum ultraviolet spectrograph system for plasma diagnostics
Yoshikawa, M.; Kubota, Y.; Kobayashi, T.; Saito, M.; Numada, N.; Nakashima, Y.; Cho, T.; Koguchi, H.; Yagi, Y.; Yamaguchi, N.
2004-10-01
A space- and time-resolving vacuum ultraviolet (VUV) spectrograph system has been applied to diagnose impurity ions behavior in plasmas produced in the tandem mirror GAMMA 10 and the reversed field pinch TPE-RX. We have carried out ray tracing calculations for obtaining the characteristics of the VUV spectrograph and calibration experiments to measure the absolute sensitivities of the VUV spectrograph system for the wavelength range from 100 to 1100 A. By changing the incident angle, 50.6 deg. -51.4 deg., to the spectrograph whose nominal incident angle is 51 deg., we can change the observing spectral range of the VUV spectrograph. In this article, we show the ray tracing calculation results and absolute sensitivities when the angle of incidence into the VUV spectrograph is changed, and the results of VUV spectroscopic measurement in both GAMMA 10 and TPE-RX plasmas.
MSTAR: an absolute metrology system with submicrometer accuracy
NASA Astrophysics Data System (ADS)
Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert D.; Burger, Johan; Steier, Willian H.; Ahn, Seh-Won; Fetterman, Harrold R.
2004-10-01
Laser metrology systems are a key component of stellar interferometers, used to monitor path lengths and dimensions internal to the instrument. Most interferometers use 'relative' metrology, in which the integer number of wavelengths along the path is unknown, and the measurement of length is ambiguous. Changes in the path length can be measured relative to an initial calibration point, but interruption of the metrology beam at any time requires a re-calibration of the system. The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. We describe the design of the system, show results for target distances up to 1 meter, and demonstrate how the system can be scaled to kilometer-scale distances. In recent experiments, we have used white light interferometry to augment the 'truth' measurements and validate the zero-point of the system. MSTAR is a general-purpose tool for conveniently measuring length with much greater accuracy than was previously possible, and has a wide range of possible applications.
Reference coordinate systems: An update. Supplement 11
NASA Technical Reports Server (NTRS)
Mueller, Ivan I.
1988-01-01
A common requirement for all geodetic investigations is a well-defined coordinate system attached to the earth in some prescribed way, as well as a well-defined inertial coordinate system in which the motions of the terrestrial frame can be monitored. The paper deals with the problems encountered when establishing such coordinate systems and the transformations between them. In addition, problems related to the modeling of the deformable earth are discussed. This paper is an updated version of the earlier work, Reference Coordinate Systems for Earth Dynamics: A Preview, by the author.
Sensitivity analysis approach to multibody systems described by natural coordinates
NASA Astrophysics Data System (ADS)
Li, Xiufeng; Wang, Yabin
2014-03-01
The classical natural coordinate modeling method which removes the Euler angles and Euler parameters from the governing equations is particularly suitable for the sensitivity analysis and optimization of multibody systems. However, the formulation has so many principles in choosing the generalized coordinates that it hinders the implementation of modeling automation. A first order direct sensitivity analysis approach to multibody systems formulated with novel natural coordinates is presented. Firstly, a new selection method for natural coordinate is developed. The method introduces 12 coordinates to describe the position and orientation of a spatial object. On the basis of the proposed natural coordinates, rigid constraint conditions, the basic constraint elements as well as the initial conditions for the governing equations are derived. Considering the characteristics of the governing equations, the newly proposed generalized-α integration method is used and the corresponding algorithm flowchart is discussed. The objective function, the detailed analysis process of first order direct sensitivity analysis and related solving strategy are provided based on the previous modeling system. Finally, in order to verify the validity and accuracy of the method presented, the sensitivity analysis of a planar spinner-slider mechanism and a spatial crank-slider mechanism are conducted. The test results agree well with that of the finite difference method, and the maximum absolute deviation of the results is less than 3%. The proposed approach is not only convenient for automatic modeling, but also helpful for the reduction of the complexity of sensitivity analysis, which provides a practical and effective way to obtain sensitivity for the optimization problems of multibody systems.
On a new coordinate system with astrophysical application: Spiral coordinates
NASA Astrophysics Data System (ADS)
Campos, L. M. B. C.; Gil, P. J. S.
In this presentation are introduced spiral coordinates, which are a particular case of conformal coordinates, i.e. orthogonal curvelinear coordinates with equal factors along all coordinate axis. The spiral coordinates in the plane have as coordinate curves two families of logarithmic spirals, making a constant angle, respectively phi and pi / 2-phi, with all radial lines, where phi is a parameter. They can be obtained from a complex function, representing a spiral potential flow, due to the superposition of a source/sink with a vortex; the parameter phi in this case specifies the ratio of the ass flux of source/sink to the circulation of the vortex. Regardless of hydrodynamical or other interpretations, spiral coordinates are particulary convenient in situation where physical quantities vary only along a logarithmicspiral. The example chosen is the propagation of Alfven waves along a logarithmic spiral, as an approximation to Parker's spiral. The equation of dissipative MHD are written in spiral coordinates, and eliminated to specify the Alfven wave equation in spiral coordinates; the latter is solved exactly in terms of Bessel functions, and the results analyzed for values of the parameters corresponding to the solar wind.
Examination of Eulerian and Lagrangian Coordinate Systems.
ERIC Educational Resources Information Center
Remillard, Wilfred J.
1978-01-01
Studies the relationship between Eulerian and Lagrangian coordinate systems with the help of computer plots of variables such as density and particle displacement. Gives examples which illustrate the differences in the shape of a traveling wave as seen by observers in the two systems. (Author/GA)
Information Systems Coordinate Emergency Management
NASA Technical Reports Server (NTRS)
2012-01-01
-changing planet. This information can be captured, analyzed, and visualized by geographic information systems (GIS) to produce maps, charts, and other tools that can reveal information essential to a wide variety of applications including emergency management. Knowing precise, real-time information about the size, location, environmental conditions, and resulting damage of an event like a flood or wildfire as well as the location and numbers of emergency responders and other resources contributes directly to the effectiveness of disaster mitigation. The need for such information is also evident when responding to homeland security threats, such as a terrorist attack. Recognizing the value of its geospatial information resources for this and other purposes, in 1998 Stennis and the state of Mississippi partnered to form what became the Enterprise for Innovative Geospatial Solutions (EIGS) industry cluster, supporting the growth of remote sensing and GIS-based research and business. As part of EIGS, several companies partnered with NASA through dual use and Small Business Innovation Research (SBIR) contracts. Among those was NVision.
Galgon, Anne K.; Shewokis, Patricia A.
2016-01-01
The objectives of this communication are to present the methods used to calculate mean absolute relative phase (MARP), deviation phase (DP) and point estimate relative phase (PRP) and compare their utility in measuring postural coordination during the performance of a serial reaching task. MARP and DP are derived from continuous relative phase time series representing the relationship between two body segments or joints during movements. MARP is a single measure used to quantify the coordination pattern and DP measures the stability of the coordination pattern. PRP also quantifies coordination patterns by measuring the relationship between the timing of maximal or minimal angular displacements of two segments within cycles of movement. Seven young adults practiced a bilateral serial reaching task 300 times over 3 days. Relative phase measures were used to evaluate inter-joint relationships for shoulder-hip (proximal) and hip-ankle (distal) postural coordination at early and late learning. MARP, PRP and DP distinguished between proximal and distal postural coordination. There was no effect of practice on any of the relative phase measures for the group, but individual differences were seen over practice. Combined, MARP and DP estimated stability of in-phase and anti-phase postural coordination patterns, however additional qualitative movement analyses may be needed to interpret findings in a serial task. We discuss the strengths and limitations of using MARP and DP and compare MARP and DP to PRP measures in assessing coordination patterns in the context of various types of skillful tasks. Key points MARP, DP and PRP measures coordination between segments or joint angles Advantages and disadvantages of each measure should be considered in relationship to the performance task MARP and DP may capture coordination patterns and stability of the patterns during discrete tasks or phases of movements within a task PRP and SD or PRP may capture coordination patterns and
A portable system for measuring the absolute geographic location of distant objects
NASA Astrophysics Data System (ADS)
Kuscer, Lovro; Diaci, Janez
2010-10-01
This contribution presents the development of a lightweight, man-portable system for measuring the absolute geographic location of distant objects. The system is built entirely from COTS (Commercial Of-The-Shelf) components that are controlled using custom software and hardware solutions. It consists of a laser rangefinder, an electronic compass and inclinometer, an optical incremental encoder, a GPS receiver, a CMOS camera, an LCOS viewfinder and an FPGA module that serves as a system controller. With the use of the FPGA, low power consumption and high processing power was achieved. The user interface comprises the viewfinder and a multidirectional button. While performing measurements, the live image of the target, sensor data and calculated coordinates are displayed in the viewfinder. The measuring system also features an SD card slot for data storage and WLAN connectivity to transfer the acquired data to a geographic information system. The contribution also presents the results of field tests used to verify the system operation and Monte Carlo simulations employed to evaluate its measuring characteristics.
Distributed sensor coordination for advanced energy systems
Tumer, Kagan
2015-03-12
Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectives and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement, heterogeneous sensor
Existence of frozen-in coordinate systems
NASA Technical Reports Server (NTRS)
Chertkov, A. D.
1995-01-01
The 'frozen-in' coordinate systems were first introduced in the works on 'reconnection' and 'magnetic barrier' theories (see review by M.l.Pudovkin and V.S.Semenov, Space Sci. Rev. 41,1 1985). The idea was to utilize the mathematical apparatus developed for 'general relativity' theory to simplify obtaining solutions to the ideal MHD equations set. Magnetic field (B), plasma velocity (v), and their vector product were used as coordinate vectors. But there exist no stationary solutions of ideal MHD set that satisfies the required boundary conditions at infinity (A.D.Chertkov, Solar Wind Seven Conf.,Pergamon Press,1992,165) having non-zero vector product of v and B where v and B originate from the same sphere. The existence of a solution is the hidden mine of the mentioned theories. The solution is constructed in the coordinate system, which is unknown and indeterminate before obtaining this solution. A substitution of the final solution must be done directly into the initial MHD set in order to check the method. One can demonstrate that 'solutions' of Petschek's problem, obtained by 'frozen-in' coordinate systems, does not satisfy just the 'frozen-in' equation, i.e. induction equation. It stems from the fact that Petschek's 're-connection' model, treated as a boundary problem, is over determined. This problem was incorrectly formulated.
Model reduction in the physical coordinate system
NASA Technical Reports Server (NTRS)
Yae, K. Harold; Joeng, K. Y.
1989-01-01
In the dynamics modeling of a flexible structure, finite element analysis employs reduction techniques, such as Guyan's reduction, to remove some of the insignificant physical coordinates, thus producing a dynamics model that has smaller mass and stiffness matrices. But this reduction is limited in the sense that it removes certain degrees of freedom at a node points themselves in the model. From the standpoint of linear control design, the resultant model is still too large despite the reduction. Thus, some form of the model reduction is frequently used in control design by approximating a large dynamical system with a fewer number of state variables. However, a problem arises from the placement of sensors and actuators in the reduced model, because a model usually undergoes, before being reduced, some form of coordinate transformations that do not preserve the physical meanings of the states. To correct such a problem, a method is developed that expresses a reduced model in terms of a subset of the original states. The proposed method starts with a dynamic model that is originated and reduced in finite element analysis. Then the model is converted to the state space form, and reduced again by the internal balancing method. At this point, being in the balanced coordinate system, the states in the reduced model have no apparent resemblance to those of the original model. Through another coordinate transformation that is developed, however, this reduced model is expressed by a subset of the original states.
Reda, I.; Zeng, J.; Scheuch, J.; Hanssen, L.; Wilthan, B.; Myers, D.; Stoffel, T.
2012-03-01
This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180{sup o} view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U{sub 95}) of {+-}3.96 W m{sup 02} with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m{sup 2} lower than that
NASA Astrophysics Data System (ADS)
Reda, Ibrahim; Zeng, Jinan; Scheuch, Jonathan; Hanssen, Leonard; Wilthan, Boris; Myers, Daryl; Stoffel, Tom
2012-03-01
This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180° view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U95) of ±3.96 W m-2 with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two
A coordinated approach to control system modifications
Lance, G.J.; Babuka, R.D.; Ricker, S.
1995-10-01
This paper describes the structured approach to a major control system retrofit. The project included replacing out-dated controls hardware with a distributed control system as part of a low NO{sub x} conversion project. The success of the coordinated approach used for this project depended on many key factors. The most important factor was strength of the EKPC/B and W relationship that united B and W design and installation expertise with EKPC operations. This relationship provided a comprehensive forum for information exchange between all parties involved. The design documents (P and IDs, SRSs, I/O Lists, and SITs) provided a conduit for technical information exchange. The integrated schedule was used as a dynamic road map to drive, guide and coordinate the project. The schedule provided direction to all contributing organizations through the engineering, installation, and start-up phases. The labor partnering approach to electrical and instrumentation installation infused valuable installation expertise into the project. The lessons learned sessions provided important performance feedback. These sessions measured the effectiveness of overall communication and led to process improvement. The success of this project is directly attributable to the dedication and coordinated approach of the EKPC/B and W project team.
Which coordinate system for modelling path integration?
Vickerstaff, Robert J; Cheung, Allen
2010-03-21
Path integration is a navigation strategy widely observed in nature where an animal maintains a running estimate, called the home vector, of its location during an excursion. Evidence suggests it is both ancient and ubiquitous in nature, and has been studied for over a century. In that time, canonical and neural network models have flourished, based on a wide range of assumptions, justifications and supporting data. Despite the importance of the phenomenon, consensus and unifying principles appear lacking. A fundamental issue is the neural representation of space needed for biological path integration. This paper presents a scheme to classify path integration systems on the basis of the way the home vector records and updates the spatial relationship between the animal and its home location. Four extended classes of coordinate systems are used to unify and review both canonical and neural network models of path integration, from the arthropod and mammalian literature. This scheme demonstrates analytical equivalence between models which may otherwise appear unrelated, and distinguishes between models which may superficially appear similar. A thorough analysis is carried out of the equational forms of important facets of path integration including updating, steering, searching and systematic errors, using each of the four coordinate systems. The type of available directional cue, namely allothetic or idiothetic, is also considered. It is shown that on balance, the class of home vectors which includes the geocentric Cartesian coordinate system, appears to be the most robust for biological systems. A key conclusion is that deducing computational structure from behavioural data alone will be difficult or impossible, at least in the absence of an analysis of random errors. Consequently it is likely that further theoretical insights into path integration will require an in-depth study of the effect of noise on the four classes of home vectors. PMID:19962387
System-Level Planning, Coordination, and Communication
Kanter, Robert K.; Dries, David; Luyckx, Valerie; Lim, Matthew L.; Wilgis, John; Anderson, Michael R.; Sarani, Babak; Hupert, Nathaniel; Mutter, Ryan; Devereaux, Asha V.; Christian, Michael D.; Kissoon, Niranjan; Christian, Michael D.; Devereaux, Asha V.; Dichter, Jeffrey R.; Kissoon, Niranjan; Rubinson, Lewis; Amundson, Dennis; Anderson, Michael R.; Balk, Robert; Barfield, Wanda D.; Bartz, Martha; Benditt, Josh; Beninati, William; Berkowitz, Kenneth A.; Daugherty Biddison, Lee; Braner, Dana; Branson, Richard D; Burkle, Frederick M.; Cairns, Bruce A.; Carr, Brendan G.; Courtney, Brooke; DeDecker, Lisa D.; De Jong, Marla J.; Dominguez-Cherit, Guillermo; Dries, David; Einav, Sharon; Erstad, Brian L.; Etienne, Mill; Fagbuyi, Daniel B.; Fang, Ray; Feldman, Henry; Garzon, Hernando; Geiling, James; Gomersall, Charles D.; Grissom, Colin K.; Hanfling, Dan; Hick, John L.; Hodge, James G.; Hupert, Nathaniel; Ingbar, David; Kanter, Robert K.; King, Mary A.; Kuhnley, Robert N.; Lawler, James; Leung, Sharon; Levy, Deborah A.; Lim, Matthew L.; Livinski, Alicia; Luyckx, Valerie; Marcozzi, David; Medina, Justine; Miramontes, David A.; Mutter, Ryan; Niven, Alexander S.; Penn, Matthew S.; Pepe, Paul E.; Powell, Tia; Prezant, David; Reed, Mary Jane; Rich, Preston; Rodriquez, Dario; Roxland, Beth E.; Sarani, Babak; Shah, Umair A.; Skippen, Peter; Sprung, Charles L.; Subbarao, Italo; Talmor, Daniel; Toner, Eric S.; Tosh, Pritish K.; Upperman, Jeffrey S.; Uyeki, Timothy M.; Weireter, Leonard J.; West, T. Eoin; Wilgis, John; Ornelas, Joe; McBride, Deborah; Reid, David; Baez, Amado; Baldisseri, Marie; Blumenstock, James S.; Cooper, Art; Ellender, Tim; Helminiak, Clare; Jimenez, Edgar; Krug, Steve; Lamana, Joe; Masur, Henry; Mathivha, L. Rudo; Osterholm, Michael T.; Reynolds, H. Neal; Sandrock, Christian; Sprecher, Armand; Tillyard, Andrew; White, Douglas; Wise, Robert; Yeskey, Kevin
2014-01-01
BACKGROUND: System-level planning involves uniting hospitals and health systems, local/regional government agencies, emergency medical services, and other health-care entities involved in coordinating and enabling care in a major disaster. We reviewed the literature and sought expert opinions concerning system-level planning and engagement for mass critical care due to disasters or pandemics and offer suggestions for system-planning, coordination, communication, and response. The suggestions in this chapter are important for all of those involved in a pandemic or disaster with multiple critically ill or injured patients, including front-line clinicians, hospital administrators, and public health or government officials. METHODS: The American College of Chest Physicians (CHEST) consensus statement development process was followed in developing suggestions. Task Force members met in person to develop nine key questions believed to be most relevant for system-planning, coordination, and communication. A systematic literature review was then performed for relevant articles and documents, reports, and other publications reported since 1993. No studies of sufficient quality were identified upon which to make evidence-based recommendations. Therefore, the panel developed expert opinion-based suggestions using a modified Delphi process. RESULTS: Suggestions were developed and grouped according to the following thematic elements: (1) national government support of health-care coalitions/regional health authorities (HC/RHAs), (2) teamwork within HC/RHAs, (3) system-level communication, (4) system-level surge capacity and capability, (5) pediatric patients and special populations, (6) HC/RHAs and networks, (7) models of advanced regional care systems, and (8) the use of simulation for preparedness and planning. CONCLUSIONS: System-level planning is essential to provide care for large numbers of critically ill patients because of disaster or pandemic. It also entails a
AST: World Coordinate Systems in Astronomy
NASA Astrophysics Data System (ADS)
Berry, David S.; Warren-Smith, Rodney F.
2014-04-01
The AST library provides a comprehensive range of facilities for attaching world coordinate systems to astronomical data, for retrieving and interpreting that information in a variety of formats, including FITS-WCS, and for generating graphical output based on it. Core projection algorithms are provided by WCSLIB (ascl:1108.003) and astrometry is provided by the PAL and SOFA (ascl:1403.026) libraries. AST bindings are available in Python (pyast), Java (JNIAST) and Perl (Starlink::AST). AST is used as the plotting and astrometry library in DS9 and GAIA, and is distributed separately and as part of the Starlink software collection.
Distributed Sensor Coordination for Advanced Energy Systems
Tumer, Kagan
2013-07-31
The ability to collect key system level information is critical to the safe, efficient and reli- able operation of advanced energy systems. With recent advances in sensor development, it is now possible to push some level of decision making directly to computationally sophisticated sensors, rather than wait for data to arrive to a massive centralized location before a decision is made. This type of approach relies on networked sensors (called “agents” from here on) to actively collect and process data, and provide key control deci- sions to significantly improve both the quality/relevance of the collected data and the as- sociating decision making. The technological bottlenecks for such sensor networks stem from a lack of mathematics and algorithms to manage the systems, rather than difficulties associated with building and deploying them. Indeed, traditional sensor coordination strategies do not provide adequate solutions for this problem. Passive data collection methods (e.g., large sensor webs) can scale to large systems, but are generally not suited to highly dynamic environments, such as ad- vanced energy systems, where crucial decisions may need to be reached quickly and lo- cally. Approaches based on local decisions on the other hand cannot guarantee that each agent performing its task (maximize an agent objective) will lead to good network wide solution (maximize a network objective) without invoking cumbersome coordination rou- tines. There is currently a lack of algorithms that will enable self-organization and blend the efficiency of local decision making with the system level guarantees of global decision making, particularly when the systems operate in dynamic and stochastic environments. In this work we addressed this critical gap and provided a comprehensive solution to the problem of sensor coordination to ensure the safe, reliable, and robust operation of advanced energy systems. The differentiating aspect of the proposed work is in shift- ing
Tuning and Robustness Analysis for the Orion Absolute Navigation System
NASA Technical Reports Server (NTRS)
Holt, Greg N.; Zanetti, Renato; D'Souza, Christopher
2013-01-01
The Orion Multi-Purpose Crew Vehicle (MPCV) is currently under development as NASA's next-generation spacecraft for exploration missions beyond Low Earth Orbit. The MPCV is set to perform an orbital test ight, termed Exploration Flight Test 1 (EFT-1), some time in late 2014. The navigation system for the Orion spacecraft is being designed in a Multi-Organizational Design Environment (MODE) team including contractor and NASA personnel. The system uses an Extended Kalman Filter to process measurements and determine the state. The design of the navigation system has undergone several iterations and modi cations since its inception, and continues as a work-in-progress. This paper seeks to show the e orts made to-date in tuning the lter for the EFT-1 mission and instilling appropriate robustness into the system to meet the requirements of manned space ight. The results generally show Monte Carlo error performance bounded by the lter uncertainty for all phases of ight. Some future items of investigation are presented related to suspected anomalies in the trajectory truth reference le.
NASA Astrophysics Data System (ADS)
Shastry, Abhay; Stafford, Charles A.
2015-12-01
We consider a question motivated by the third law of thermodynamics: Can there be a local temperature arbitrarily close to absolute zero in a nonequilibrium quantum system? We consider nanoscale quantum conductors with the source reservoir held at finite temperature and the drain held at or near absolute zero, a problem outside the scope of linear response theory. We obtain local temperatures close to absolute zero when electrons originating from the finite temperature reservoir undergo destructive quantum interference. The local temperature is computed by numerically solving a nonlinear system of equations describing equilibration of a scanning thermoelectric probe with the system, and we obtain excellent agreement with analytic results derived using the Sommerfeld expansion. A local entropy for a nonequilibrium quantum system is introduced and used as a metric quantifying the departure from local equilibrium. It is shown that the local entropy of the system tends to zero when the probe temperature tends to zero, consistent with the third law of thermodynamics.
Multi-channel data acquisition system with absolute time synchronization
NASA Astrophysics Data System (ADS)
Włodarczyk, Przemysław; Pustelny, Szymon; Budker, Dmitry; Lipiński, Marcin
2014-11-01
We present a low-cost, stand-alone global-time-synchronized data acquisition system. Our prototype allows recording up to four analog signals with a 16-bit resolution in variable ranges and a maximum sampling rate of 1000 S/s. The system simultaneously acquires readouts of external sensors e.g. magnetometer or thermometer. A complete data set, including a header containing timestamp, is stored on a Secure Digital (SD) card or transmitted to a computer using Universal Serial Bus (USB). The estimated time accuracy of the data acquisition is better than ±200 ns. The device is intended for use in a global network of optical magnetometers (the Global Network of Optical Magnetometers for Exotic physics - GNOME), which aims to search for signals heralding physics beyond the Standard Model, that can be generated by ordinary spin coupling to exotic particles or anomalous spin interactions.
Tuning and Robustness Analysis for the Orion Absolute Navigation System
NASA Technical Reports Server (NTRS)
Holt, Greg N.; Zanetti, Renato; D'Souza, Christopher
2013-01-01
The Orion Multi-Purpose Crew Vehicle (MPCV) is currently under development as NASA's next-generation spacecraft for exploration missions beyond Low Earth Orbit. The MPCV is set to perform an orbital test flight, termed Exploration Flight Test 1 (EFT-1), some time in late 2014. The navigation system for the Orion spacecraft is being designed in a Multi-Organizational Design Environment (MODE) team including contractor and NASA personnel. The system uses an Extended Kalman Filter to process measurements and determine the state. The design of the navigation system has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to show the efforts made to-date in tuning the filter for the EFT-1 mission and instilling appropriate robustness into the system to meet the requirements of manned space ight. Filter performance is affected by many factors: data rates, sensor measurement errors, tuning, and others. This paper focuses mainly on the error characterization and tuning portion. Traditional efforts at tuning a navigation filter have centered around the observation/measurement noise and Gaussian process noise of the Extended Kalman Filter. While the Orion MODE team must certainly address those factors, the team is also looking at residual edit thresholds and measurement underweighting as tuning tools. Tuning analysis is presented with open loop Monte-Carlo simulation results showing statistical errors bounded by the 3-sigma filter uncertainty covariance. The Orion filter design uses 24 Exponentially Correlated Random Variable (ECRV) parameters to estimate the accel/gyro misalignment and nonorthogonality. By design, the time constant and noise terms of these ECRV parameters were set to manufacturer specifications and not used as tuning parameters. They are included in the filter as a more analytically correct method of modeling uncertainties than ad-hoc tuning of the process noise. Tuning is explored for the
Quipus and System of Coordinated Precession
NASA Astrophysics Data System (ADS)
Campos, T. C.
2004-05-01
The Incas of ancient Peru possessed no writing. Instead, they developed a unique system expressed on spatial arrays of colored knotted cords called Quipus to record and transmit information throughout their vast empire. In their thorough description of quipus, Ascher & Ascher observed that in two cases the numbers registered in their strings have a very special relationship to each other. For this to occur the numbers must have been obtained through the multiplication of whole numbers by fractions or decimals, operations apparently beyond the arithmetic knowledge of the Incas. The quipus AS120 and AS143, coming from Ica (Peru) and conserved in the Museum of Berlin has the suitable characteristics previously. In the AS143 there is a the relationship with the systems of coordinated precession (tilt of Earth's spin axis (40036); eccentricity of Earth's orbit (97357); and precession of equinoxes (between 18504 and 23098)). For the history of the Earth are necessary an chronometer natural to coordinate and to classify the observations and this chronometer comes to be the vernal point, defining the vernal point as" a sensitive axis of maximum conductivity" as itdemonstrates it the stability of the geomagnetic equator (inclination of the field is zero grades), in the year 1939 calculated with the IGRF from the year 1900 up to the 2004 and that it is confirmed with tabulated data of the Geophysical Institute of Huancayo (Peru),from that date until this year (2004) and this fluctuating between the 12-14 South.,on the other hand in the area of Brazil it has advanced very quickly toward the north, and above to 108 km. approximately it is located the equatorial electrojet that is but intense in the equinoxes in South America. And this stability from the point of view of the precession of the equinoxes this coinciding with the entrance of the apparent sun for the constellation of Aquarius, being this mechanism the base to establish a system of coordinated precession where it is
System providing limit switch function with simultaneous absolute position output
NASA Technical Reports Server (NTRS)
Alhorn, Dean C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)
2006-01-01
A limit and position sensing system includes a sensor assembly and an emitter. The sensor assembly includes first and second electrical conductors arranged in opposing parallel planes. The first electrical conductor is coiled outwardly from either end thereof in a clockwise fashion to form a first coil region and a second coil region. The second electrical conductor forms a single coil with portions of the single coil's rings lying between the first end and second end of the first electrical conductor being parallel to an axis of the first electrical conductor's plane. Ferromagnetic material is aligned with the first and second electrical conductors and spans beyond (a) the first and second ends of the first electrical conductor, and (b) the portions of the rings of the second electrical conductor's single coil that lie between the first end and second end of the first electrical conductor. The emitter is spaced apart from the sensor assembly and transmits a periodic electromagnetic wave towards the sensor assembly.
NASA Astrophysics Data System (ADS)
Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu
2015-10-01
Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.
A topological coordinate system for the diamond cubic grid.
Čomić, Lidija; Nagy, Benedek
2016-09-01
Topological coordinate systems are used to address all cells of abstract cell complexes. In this paper, a topological coordinate system for cells in the diamond cubic grid is presented and some of its properties are detailed. Four dependent coordinates are used to address the voxels (triakis truncated tetrahedra), their faces (hexagons and triangles), their edges and the points at their corners. Boundary and co-boundary relations, as well as adjacency relations between the cells, can easily be captured by the coordinate values. Thus, this coordinate system is apt for implementation in various applications, such as visualizations, morphological and topological operations and shape analysis. PMID:27580205
ERIC Educational Resources Information Center
Washington Office of the State Superintendent of Public Instruction, Olympia.
This report outlines the roles and responsibilities, pertaining to the improvement amd coordination of statewide teacher inservice, of the Superintendent of Public Instruction (SPI) in the state of Washington. After a field-based research study was conducted, a system was devised by which the SPI can improve coordination of staff development…
Easy Absolute Values? Absolutely
ERIC Educational Resources Information Center
Taylor, Sharon E.; Mittag, Kathleen Cage
2015-01-01
The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…
Orbital elements and absolute dimensions of the eclipsing system LY Aurigae
NASA Technical Reports Server (NTRS)
Mccluskey, G. E., Jr.; Kondo, Y.
1974-01-01
Orbital solutions were obtained for the early-type eclipsing binary LY Aurigae from the light curves obtained with the OAO-2 by Heap and from the V light curve obtained from ground-based observations by Mayer and Horak. The solutions take into account the existence of a nearby companion not accounted for by previous investigators. The spectroscopic observations by Mayer and Batten were used to compute absolute dimensions for the binary orbit and for each component. This binary system presents an unique opportunity to determine accurately the absolute dimensions of an O9.5 III star.
Absolute Definition of Phase Shift in the Elastic Scattering of a Particle from Compound Systems
NASA Technical Reports Server (NTRS)
Temkin, A.
1961-01-01
The projection of the target wave function on the total wave function of a scattered particle interacting with the target system is used to define an absolute phase shift including any multiples of pi. With this definition of the absolute phase shift, one can prove rigorously in the limit of zero energy for s-wave electrons scattered from atomic hydrogen that the triplet phase shift must approach a nonzero multiple of pi. One can further show that at least one pi of this phase shift is not connected with the existence of a bound state of the H- ion.
Maple (Computer Algebra System) in Teaching Pre-Calculus: Example of Absolute Value Function
ERIC Educational Resources Information Center
Tuluk, Güler
2014-01-01
Modules in Computer Algebra Systems (CAS) make Mathematics interesting and easy to understand. The present study focused on the implementation of the algebraic, tabular (numerical), and graphical approaches used for the construction of the concept of absolute value function in teaching mathematical content knowledge along with Maple 9. The study…
Mare Orientale Prime Meridian lunar coordinate system
NASA Astrophysics Data System (ADS)
Walden, B.; York, C.; McGown, R.; Billings, T.
The Moon was the first extraterrestrial body to be mapped. From 1514 to 1840, navigators sailing the open seas needed accurate lunar maps to determine longitude by the "lunar-distance" method. For the convenience of early navigators, astronomers and selenographers, the lunar prime meridian was made to bisect the lunar disk as seen from Earth, formalized as the present Mean Earth / Polar Axis system. In 1961, the International Astronomical Union reversed lunar east and west to avoid confusion by astronauts and their controllers, so that now Mare Orientale -- the Eastern Sea -- lies on the Moon's western limb. By international agreement in 1974, lunar longitude was defined to increase eastward from zero to 360 degrees and prime meridians are generally defined by an observable feature. Examination of popular lunar maps indicates these newer standards are not widely accepted. Modern navigation no longer relies on the Moon. Lunar maps are now made by satellite imagery from lunar orbit. Today, humankind anticipates navigating the Moon itself. A relatively simple change to the lunar coordinate system could benefit upcoming lunar activities and promote acceptance of a 360 degree standard: move the lunar prime meridian. We propose the lunar prime meridian intersect some natural monument that most nearly represents the center longitude of Mare Orientale (perhaps crater Hohmann), and longitude increase eastward from zero to 360 degrees. Mare Orientale is a dramatic large "target," easily identifiable from space. Nearside traffic will use low longitude numbers from zero to r ughly 180 degrees,o and will not frequently cross this prime meridian. Earth's angle above the eastern horizon equals approximate longitude. Low and high longitude numbers will reflect the distinctive nearside and farside geological domains. The face of the Moon as seen from Earth will no longer be split in two. Calculations are simplified and sources of error eliminated. This system is more convenient and
Coordinate System Issues in Binary Star Computations
NASA Astrophysics Data System (ADS)
Kaplan, George H.
2015-08-01
It has been estimated that half of all stars are components of binary or multiple systems. Yet the number of known orbits for astrometric and spectroscopic binary systems together is less than 7,000 (including redundancies), almost all of them for bright stars. A new generation of deep all-sky surveys such as Pan-STARRS, Gaia, and LSST are expected to lead to the discovery of millions of new systems. Although for many of these systems, the orbits may be undersampled initially, it is to be expected that combinations of new and old data sources will eventually lead to many more orbits being known. As a result, a revolution in the scientific understanding of these systems may be upon us.The current database of visual (astrometric) binary orbits represents them relative to the “plane of the sky”, that is, the plane orthogonal to the line of sight. Although the line of sight to stars constantly changes due to proper motion, aberration, and other effects, there is no agreed upon standard for what line of sight defines the orbital reference plane. Furthermore, the computation of differential coordinates (component B relative to A) for a given date must be based on the binary system’s direction at that date. Thus, a different “plane of the sky” is appropriate for each such date, i.e., each observation. However, projection effects between the reference planes, differential aberration, and the curvature of the sky are generally neglected in such computations. Usually the only correction applied is for the change in the north direction (position angle zero) due to precession (and sometimes also proper motion). This paper will present an algorithm for a more complete model of the geometry involved, and will show that such a model is necessary to avoid errors in the computed observables that are significant at modern astrometric accuracy. The paper will also suggest where conventions need to be established to avoid ambiguities in how quantities related to binary star
Space telescope coordinate systems, symbols, and nomenclature definitions
NASA Technical Reports Server (NTRS)
Kennel, H. F.
1976-01-01
The major coordinate systems as well as the transformations and transformation angles between them, for the Space Telescope are defined. The coordinate systems were primarily developed for use in pointing and control system analysis and simulation. Additional useful information (on nomenclature, symbols, quaternion operations, etc.) is also contained.
The Path to an Up-to-date Absolute Gravity Reference System
NASA Astrophysics Data System (ADS)
Wilmes, H.; Falk, R.; Wziontek, H.
2014-12-01
The determination of precise gravity field parameters is of great importance in a period in which earth sciences are achieving the necessary accuracy to monitor and document global change processes. This is the reason why experts from geodesy and metrology joined in a successful cooperation to make absolute gravity observations traceable to SI quantities, to improve the metrological kilogram definition and to monitor mass movements and smallest height changes for geodetic and geophysical applications. How can we determine such a gravity reference system and secure it over multiple decades? Precise knowledge of the gravity acceleration and definition of standards, models and corrections are an important prerequisite to the definition of the gravity system. Over more than three decades, the absolute gravity community cooperated successfully to obtain the gravity reference in comparisons at intervals of 4 years and to certify metrological equivalence between National Metrology Institutes. With increasing resolution of the absolute gravimeter sensors and new measurement principles it becomes obvious that such comparisons are not sufficient for all applications. Mainly for geodetic purposes it is necessary to sub-divide comparison intervals and maintain a connected network of gravity reference sites where compared absolute gravimeters operate together with superconducting gravimeters to derive a continuous gravity reference function. By means of this distributed monitoring of the gravity reference it will also be possible to relate observations of earlier absolute gravimeters to the present-day and to future instruments. It will be possible to include new sensors like atom interferometers and in future to relate the results of precise optical clocks. With co-located space geodetic sensors like GNSS, SLR and VLBI, these reference sites fulfill the conditions of a geodetic fundamental station as a component of IAG's Global Geodetic Observing System.
Comment on 'Absolute negative mobility in a one-dimensional overdamped system'
NASA Astrophysics Data System (ADS)
Spiechowicz, J.; Kostur, M.; Łuczka, J.
2016-04-01
Recently Ru-Yin Chen et al. (Phys. Lett. A 379 (2015) 2169-2173) presented results on the absolute negative mobility (ANM) in a one-dimensional overdamped system and claimed that a new minimal model of ANM was proposed. We suggest that the authors introduced a mistake in their calculations. Then we perform a precise numerical simulation of the corresponding Langevin equation to show that the ANM phenomenon does not occur in the considered system.
A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph
NASA Astrophysics Data System (ADS)
Doerr, H.-P.; Steinmetz, T.; Holzwarth, R.; Kentischer, T.; Schmidt, W.
2012-10-01
A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut für Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.
Representation of Projection and Coordinate Systems in Engineering Graphics.
ERIC Educational Resources Information Center
Ross, William A.
1990-01-01
The existing methods for graphically illustrating projection and coordinate systems for manual and computer-aided drafting and design are examined. Inconsistencies in methods used to graphically depict first and third angle projection in texts and the lack of attention in the relationship of projection to coordinate systems are noted. (KR)
Multi-view coordinate system transformation based on robot
NASA Astrophysics Data System (ADS)
Song, Li-mei; Wang, Peng-qiang; Xi, Jiang-tao; Guo, Qing-hua; Tang, Huan; Li, Jing; Li, Xiao-jie; Zhu, Teng-da
2015-11-01
The registration of point cloud is important for large object measurement. A measurement method for coordinate system transformation based on robot is proposed in this paper. Firstly, for obtaining extrinsic parameters, the robot moves to three different positions to capture the images of three targets. Then the transformation matrix X between camera and tool center point (TCP) coordinate systems can be calculated by using the known parameters of robot and the extrinsic parameters, and finally the multi-view coordinate system can be transformed into robot coordinate system by the transformation matrix X. With the help of robot, the multi-view point cloud can be easily transformed into a unified coordinate system. By using robot, the measurement doesn't need any mark. Experimental results show that the method is effective.
Determination of Ship Approach Parameters in the Polar Coordinates System
NASA Astrophysics Data System (ADS)
Banachowicz, Andrzej; Wolski, Adam
2014-06-01
An essential aspect of the safety of navigation is avoiding collisions with other vessels and natural or man made navigational obstructions. To solve this kind of problem the navigator relies on automatic anti-collision ARPA systems, or uses a geometric method and makes radar plots. In both cases radar measurements are made: bearing (or relative bearing) on the target position and distance, both naturally expressed in the polar coordinates system originating at the radar antenna. We first convert original measurements to an ortho-Cartesian coordinate system. Then we solve collision avoiding problems in rectangular planar coordinates, and the results are transformed to the polar coordinate system. This article presents a method for an analysis of a collision situation at sea performed directly in the polar coordinate system. This approach enables a simpler geometric interpretation of a collision situation
Reference coordinate systems for Earth dynamics: A preview
NASA Technical Reports Server (NTRS)
Mueller, I. I.
1982-01-01
Geodynamics is the subject of intensive international research during last decade. A common requirement for all investigations is the necessity of a well defined coordinate system attached to the Earth in some prescribed way. In addition, a well defined inertial coordinate system is also needed in which the motions of the terrestrial system can be monitored. The problems encountered when establishing such coordinate systems and the transformations between them are presented. In addition, problems related to the modeling of the deformable Earth are discussed. Finally, action items are listed which are necessary to assure that the reference system issue is resolved early and that uniformity is assured by means of international agreements.
NASA Astrophysics Data System (ADS)
Zhang, Bing; Lin, Zhen; Zhang, Xiao; Yu, Xiang; Wei, Jiali; Wang, Xiaoping
2014-05-01
Based on an innovative application of van der Pauw's theory, a system was developed for the absolute measurement of electrolytic conductivity in aqueous solutions. An electrolytic conductivity meter was designed that uses a four-electrode system with an axial-radial two-dimensional adjustment structure coupled to an ac voltage excitation source and signal collecting circuit. The measurement accuracy, resolution and repeatability of the measurement system were examined through a series of experiments. Moreover, the measurement system and a high-precision electrolytic conductivity meter were compared using some actual water samples.
[Enriching the diagnosis announcement system with the coordination passport].
Bertrand, Nathalie
2016-05-01
The personalised care plan of a person with cancer requires proper coordination between the various professionals involved in their care at the different stages of their illness. In order to organise this coordination efficiently, for the patient as well as for the health professionals, an oncology hospital team has developed a practical and modular tool. The coordination passport enriches the diagnosis announcement system used in the hospital. PMID:27155278
Design of laser system for absolute gravimeter based on 87Rb atom interferometer
NASA Astrophysics Data System (ADS)
Zhao, Yang; Wang, Shaokai; Zhuang, Wei; Fang, Fang; Li, Tianchu
2015-08-01
We present a laser system design for an absolute gravimeter based on 87Rb atom interferometer. By skillful design, lasers with 9 different frequencies are based on two diode lasers including tapered amplifier. Two electrical feedback systems are used for laser frequency stabilization and the Raman lasers generation respectively. All other lasers are based on two Raman lasers and realized with frequency shift by acoustic optical modulators. This laser system not only has the compact and simple construction, but meets all requirements for laser power and frequency controlling for the atom interferometer. It has the characteristic of reliability and integrity.
Transformation formulas relating geodetic coordinates to a tangent to Earth, plane coordinate system
NASA Technical Reports Server (NTRS)
Credeur, L.
1981-01-01
Formulas and their approximation were developed to map geodetic position to an Earth tangent plane with an airport centered rectangular coordinate system. The transformations were developed for use in a terminal area air traffic model with deterministic aircraft traffic. The exact configured vehicle's approximation equations used in their precision microwave landing system navigation experiments.
Plasticity of Intermediate Mechanics Students' Coordinate System Choice
ERIC Educational Resources Information Center
Sayre, Eleanor C.; Wittman, Michael C.
2008-01-01
We investigate the interplay between mathematics and physics resources in intermediate mechanics students. In the mechanics course, the selection and application of coordinate systems is a consistent thread. At the University of Maine, students often start the course with a strong preference to use Cartesian coordinates, in accordance with their…
NASA Astrophysics Data System (ADS)
Liu, L.; Zhao, Y. H.; Zhang, W.; Wang, Y. R.; Wang, J. S.
2010-10-01
Similar to the study of the related problems of Earth satellites, in the research of the motion of Mars orbiter especially for low orbit satellites, it is more appropriate to choose an epoch Mars-centered and Mars-equator reference system, which indeed is called the Mars-centered celestial coordinate system. In this system, the xy plane and the direction of the x axis correspond to the mean equator and mean equinox. Similar to the precession and nutation on the Earth, the wiggling of instantaneous Mars equator causes the coordinate additional perturbations in this Mars coordinate system. The paper quotes a method which is similar to the one used in dealing with the coordinate additional perturbations of Earth. According to this method, based on the IAU2000 Mars orientation model and under the precondition of a certain accuracy, we are able to figure out the precession part of the change of Mars gravitation. This lays the foundation for further study of its influence on the Mars orbiter's orbit of precession and the solution of the corresponding coordinate additional perturbations. The obtained analytical solution is easy to use. Compared with the numerical solution with higher accuracy, the result shows that the accuracy of this analytical solution could satisfy general requirements in use. Therefore, our result verifies that a unified coordinate system, the Mars-centered celestial system in which J2000.0 is chosen as its current initial epoch, could be applied to deal with the relative problems of Mars orbiters, especially for low orbit satellites. It is different from the method we previously used in dealing with the corresponding problems of Earth satellites, where we adopted the instantaneous equator and epoch (J1950.0) mean equinox as xy plane and the direction of x axis. In contrast, the coordinate transformation brings heavy workload and certain inconvenience in relative former works in which the prior system is used. If adopting the unified coordinate
Coordinate Additional Perturbations to Mars Orbiters and Choice of Corresponding Coordinate System
NASA Astrophysics Data System (ADS)
Liu, Lin; Zhao, Yu-hui; Zhang, Wei; Wang, Yan-rong; Wang, Jia-song
2011-04-01
Similar to the study of the related problems of Earth satellites, in the research of the motion of Mars orbiter especially for low-orbit satellites, it is more appropriate to choose an epoch Mars-centered and Mars-equator reference system, which indeed is called the Mars-centered celestial coordinate system. In this system, the xy-plane and the direction of the x-axis correspond to the mean equator and mean equinox. Similar to the precession and nutation of the Earth, the wiggling of instantaneous Mars equator causes the coordinate additional perturbations in this Mars coordinate system. The paper quotes a method which is similar to the one used in dealing with the coordinate additional perturbations of Earth. According to this method, based on the IAU2000 Mars orientation model and under the precondition of a certain accuracy, we are able to figure out the precession part of the change of Mars gravitation. This lays the foundation for further study of its influence on the Mars orbiter's orbit of precession and the solution of the corresponding coordinate additional perturbations. The obtained analytical solution is easy to use. Compared with the numerical solution with higher accuracy, the result shows that the accuracy of this analytical solution could satisfy the general requirements in use. Therefore, our result verifies that a unified coordinate system, the Mars-centered celestial system in which J2000.0 is chosen as its current initial epoch, could be applied to deal with the relative problems of Mars orbiters, especially for low-orbit satellites. It is different from the method we previously used in dealing with the corresponding problems of Earth satellites, where we adopted the instantaneous equator and epoch (J1950.0) mean equinox as xy-plane and the direction of x -axis. In contrast, the coordinate transformation brings heavy workload and certain inconvenience in relative former works in which the prior system is used. If adopting the unified coordinate
Efficient system-wide coordination in noisy environments
Moreira, André A.; Mathur, Abhishek; Diermeier, Daniel; Amaral, Luís A. N.
2004-01-01
Many natural and social systems display global organization and coordination without centralized control. The origin of this global coordination is a topic of great current interest. Here we investigate a density-classification task as a model system for coordination and information processing in decentralized systems. We show that sophisticated strategies, selected under idealized conditions, are not robust to environmental changes. We also demonstrate that a simple heuristic is able to successfully complete the classification task under a broad range of environmental conditions. Our findings hint at the possibility that complex networks and ecologically efficient rules coevolve over time. PMID:15297617
Physical systems in a space with noncommutativity of coordinates
NASA Astrophysics Data System (ADS)
Gnatenko, Kh. P.
2016-01-01
We consider a space with canonical noncommutativity of coordinates. The problem of rotational symmetry breaking is studied in this space. To preserve the rotational symmetry we consider the generalization of constant matrix of noncommutativity to a tensor defined with the help of additional coordinates governed by a rotationally symmetric system. The properties of physical systems are examined in the rotationally invariant space with noncommutativity of coordinates. Namely, we consider an effect of coordinate noncommutativity on the energy levels of the hydrogen atom in the rotationally invariant noncommutative space. The motion of a particle in the uniform field is also studied in the noncommutative space with preserved rotational symmetry. On the basis of exact calculations we show that there is an effect of coordinate noncommutativity on the mass of a particle and conclude that noncommutativity causes the anisotropy of mass.
Sebai, Jihane
2016-01-01
Various organizational, functional or structural issues have led to a review of the foundations of the former health care system based on a traditional market segmentation between general practice and hospital medicine, and between health and social sectors and marked by competition between private and public sectors. The current reconfiguration of the health care system has resulted in “new” levers explained by the development of a new organizational reconfiguration of the primary health care model. Coordinated care structures (SSC) have been developed in this context by making coordination the cornerstone of relations between professionals to ensure global, continuous and quality health care. This article highlights the contributions of various theoretical approaches to the understanding of the concept of coordination in the analysis of the current specificity of health care. PMID:27392057
Unified Planetary Coordinates System: A Searchable Database of Geodetic Information
NASA Technical Reports Server (NTRS)
Becker, K. J.a; Gaddis, L. R.; Soderblom, L. A.; Kirk, R. L.; Archinal, B. A.; Johnson, J. R.; Anderson, J. A.; Bowman-Cisneros, E.; LaVoie, S.; McAuley, M.
2005-01-01
Over the past 40 years, an enormous quantity of orbital remote sensing data has been collected for Mars from many missions and instruments. Unfortunately these datasets currently exist in a wide range of disparate coordinate systems, making it extremely difficult for the scientific community to easily correlate, combine, and compare data from different Mars missions and instruments. As part of our work for the PDS Imaging Node and on behalf of the USGS Astrogeology Team, we are working to solve this problem and to provide the NASA scientific research community with easy access to Mars orbital data in a unified, consistent coordinate system along with a wide variety of other key geometric variables. The Unified Planetary Coordinates (UPC) system is comprised of two main elements: (1) a database containing Mars orbital remote sensing data computed using a uniform coordinate system, and (2) a process by which continual maintainance and updates to the contents of the database are performed.
Compound Words: A Problem in Post-Coordinate Retrieval Systems
ERIC Educational Resources Information Center
Jones, Kevin P.
1971-01-01
Compound words cause some difficulty in post-coordinate indexing systems: if too many are fractured, or the wrong categories are selected for fracturing noise will be produced at unacceptable levels on retrieval. (Author/MM)
Measurement system for 3-D foot coordinates and parameters
NASA Astrophysics Data System (ADS)
Liu, Guozhong; Li, Yunhui; Wang, Boxiong; Shi, Hui; Luo, Xiuzhi
2008-12-01
The 3-D foot-shape measurement system based on laser-line-scanning principle and the model of the measurement system were presented. Errors caused by nonlinearity of CCD cameras and caused by installation can be eliminated by using the global calibration method for CCD cameras, which based on nonlinear coordinate mapping function and the optimized method. A local foot coordinate system is defined with the Pternion and the Acropodion extracted from the boundaries of foot projections. The characteristic points can thus be located and foot parameters be extracted automatically by the local foot coordinate system and the related sections. Foot measurements for about 200 participants were conducted and the measurement results for male and female participants were presented. 3-D foot coordinates and parameters measurement makes it possible to realize custom-made shoe-making and shows great prosperity in shoe design, foot orthopaedic treatment, shoe size standardization, and establishment of a feet database for consumers.
Local and global navigational coordinate systems in desert ants.
Collett, Matthew; Collett, Thomas S
2009-04-01
While foraging, the desert ant Cataglyphis fortis keeps track of its position with respect to its nest through a process of path integration (PI). Once it finds food, it can then follow a direct home vector to its nest. Furthermore, it remembers the coordinates of a food site, and uses these coordinates to return to the site. Previous studies suggest, however, that it does not associate any coordinates remembered from previous trips with familiar views such that it can produce a home vector when displaced to a familiar site. We ask here whether a desert ant uses any association between PI coordinates and familiar views to ensure consistent PI coordinates as it travels along a habitual route. We describe an experiment in which we manipulated the PI coordinates an ant has when reaching a distinctive point along a habitual route on the way to a feeder. The subsequent home vectors of the manipulated ants, when displaced from the food-site to a test ground, show that also when a route memory is evoked at a significant point on the way to a food site, C. fortis does not reset its PI coordinates to those it normally has at that point. We use this result to argue that local vector memories, which encode the metric properties of a segment of a habitual route, must be encoded in a route-based coordinate system that is separate from the nest-based global coordinates. We propose a model for PI-based guidance that can account for several puzzling observations, and that naturally produces the route-based coordinate system required for learning and following local vectors. PMID:19282486
Absolutely continuous spectrum and ballistic transport in a one-dimensional quasiperiodic system
NASA Astrophysics Data System (ADS)
Pal, Biplab; Chakrabarti, Arunava
2013-02-01
We analyse a quasiperiodic arrangement of four atomic sites sitting at the vertices of a diamond shaped plaquette and single isolated sites, occupying a one dimensional backbone following a Fibonacci quasicrystal pattern. We work within a tight binding formalism. It is shown that, even with this simple deviation from pure one dimension, a definite relation between the numerical values of the system parameters will render all the single particle states completely extended. The spectrum will be absolutely continuous with the transmission completely ballistic throughout the band, completely violating the Cantor set character of the usual Fibonacci quasiperiodic chains.
High-Throughput Droplet Digital PCR System for Absolute Quantitation of DNA Copy Number
2011-01-01
Digital PCR enables the absolute quantitation of nucleic acids in a sample. The lack of scalable and practical technologies for digital PCR implementation has hampered the widespread adoption of this inherently powerful technique. Here we describe a high-throughput droplet digital PCR (ddPCR) system that enables processing of ∼2 million PCR reactions using conventional TaqMan assays with a 96-well plate workflow. Three applications demonstrate that the massive partitioning afforded by our ddPCR system provides orders of magnitude more precision and sensitivity than real-time PCR. First, we show the accurate measurement of germline copy number variation. Second, for rare alleles, we show sensitive detection of mutant DNA in a 100 000-fold excess of wildtype background. Third, we demonstrate absolute quantitation of circulating fetal and maternal DNA from cell-free plasma. We anticipate this ddPCR system will allow researchers to explore complex genetic landscapes, discover and validate new disease associations, and define a new era of molecular diagnostics. PMID:22035192
A reactive coordination scheme for a many-robot system.
Evans, K S; Unsal, C; Bay, J S
1997-01-01
This paper presents a novel approach for coordinating a homogeneous system of mobile robots using implicit communication in the form of broadcasts. The broadcast-based coordination scheme was developed for the Army Ant swarm-a system of small, relatively inexpensive mobile robots that can accomplish complex tasks by cooperating as a team. The primary drawback, however, of the Army Ant system is that the absence of a central supervisor poses difficulty in the coordination and control of the agents. Our coordination scheme provides a global "group dynamic" that controls the actions of each robot using only local interactions. Coordination of the swarm is achieved with signals we call "heartbeats". Each agent broadcasts a unique heartbeat and responds to the collective behavior of all other heartbeats. We generate heartbeats with van der Pol oscillators. In this application, we use the known properties of coupled van der Pol oscillators to create predictable group behavior. Some of the properties and behaviors of coupled van der Pol oscillators are discussed in detail. We emphasize the use of this scheme to allow agents to simultaneously perform an action such as lifting, steering, or changing speed. The results of experiments performed on three actual heartbeat circuits are presented and the behavior of the realized system is compared to simulated results. We also demonstrate the application of the coordination scheme to global speed control. PMID:18255900
Absolute stability and spatiotemporal long-range order in Floquet systems
NASA Astrophysics Data System (ADS)
von Keyserlingk, C. W.; Khemani, Vedika; Sondhi, S. L.
2016-08-01
Recent work has shown that a variety of novel phases of matter arise in periodically driven Floquet systems. Among these are many-body localized phases which spontaneously break global symmetries and exhibit novel multiplets of Floquet eigenstates separated by quantized quasienergies. Here we show that these properties are stable to all weak local deformations of the underlying Floquet drives—including those that explicitly break the defining symmetries—and that the models considered until now occupy submanifolds within these larger "absolutely stable" phases. While these absolutely stable phases have no explicit global symmetries, they spontaneously break Hamiltonian-dependent emergent symmetries, and thus continue to exhibit the novel multiplet structure. The multiplet structure in turn encodes characteristic oscillations of the emergent order parameter at multiples of the fundamental period. Altogether these phases exhibit a form of simultaneous long-range order in space and time which is new to quantum systems. We describe how this spatiotemporal order can be detected in experiments involving quenches from a broad class of initial states.
The OSU 275 system of satellite tracking station coordinates
NASA Technical Reports Server (NTRS)
Mueller, I. I.; Kumar, M.
1975-01-01
A brief review of the methods and data used in the OSU 275 geodetic system is given along with the summary of the results. Survey information regarding the tracking stations in the system is given in tabular form along with the geodetic and geophysical parameters, origin and orientation, Cartisian coordinates, and systematic differences with global and nonglobal geodetic systems.
AST: A library for modelling and manipulating coordinate systems
NASA Astrophysics Data System (ADS)
Berry, David S.; Warren-Smith, Rodney F.; Jenness, Tim
2016-04-01
In view of increased interest in object-oriented systems for describing coordinate information, we present a description of the data model used by the Starlink AST library. AST provides a comprehensive range of facilities for attaching world co-ordinate systems to astronomical data, and for retrieving and interpreting that information in a variety of formats, including FITS-WCS. AST is a mature system that has been in use for more than 17 years, and may consequently be useful as a means of informing development of similar systems in the future.
Computer transformation of partial differential equations into any coordinate system
NASA Technical Reports Server (NTRS)
Sullivan, R. D.
1977-01-01
The use of tensors to provide a compact way of writing partial differential equations in a form valid in all coordinate systems is discussed. In order to find solutions to the equations with their boundary conditions they must be expressed in terms of the coordinate system under consideration. The process of arriving at these expressions from the tensor formulation was automated by a software system, TENSR. An allied system that analyzes the resulting expressions term by term and drops those that are negligible is also described.
Precision Effects for Solar Image Coordinates Within the FITS World Coordinate System
NASA Technical Reports Server (NTRS)
Thompson, W. T.
2010-01-01
The FITS world coordinate system (WCS) provides a number of tools for precisely specifying the spatial coordinates of an image. Many of the finer details that the WCS addresses have not historically been taken into account in solar image processing. This paper examines various effects which can affect the expression of coordinates in FITS headers, to determine under what conditions such effects need to be taken into account in data analysis, and under what conditions they can be safely ignored. Effects which are examined include perspective, parallax, spherical projection, optical axis determination, speed-of-light effects, stellar aberration, gravitational deflection, and scattering and refraction at radio wavelengths. Purely instrumental effects, such as misalignment or untreated optical aberrations, are not considered. Since the value of the solar radius is an experimental quantity, the effect of adopting a specific radius value is also examined. These effects are examined in the context of a previous paper outlining a WCS standard for encoding solar coordinates in FITS files. Aspects of that previous paper are clarified and extended in the present work.
Interference coordination of heterogeneous LTE systems using remote radio heads
NASA Astrophysics Data System (ADS)
Kim, Jaewon; Lee, Donghyun; Sung, Wonjin
2013-12-01
In this paper, we present an operational strategy to mitigate co-channel interference (CCI) by using geographically distributed remote radio heads (RRHs). The inter-node CCI becomes a dominant performance degradation factor for heterogeneous network (HetNet) systems. Recently, there are emerging attempts in Third Generation Partnership Project to adopt advanced techniques to Long Term Evolution Advanced systems to mitigate CCI problems for HetNet systems, namely, the coordinated multipoint transmission (CoMP). However, the CoMP scheme cannot control the CCI generated from outside coordination boundaries. To resolve this problem, we propose a partial activation strategy by using RRHs deployed near cell edge which results in moving coverage boundary effects. Based on Monte Carlo system level simulations, performance of the conventional strategies and the presented strategy is evaluated. Simulation results show that the proposed scheme outperforms the enhanced inter-cell interference coordination and CoMP schemes especially for users located near cell edge areas.
Boncyk, Wayne C.; Markham, Brian L.; Barker, John L.; Helder, Dennis
1996-01-01
The Landsat-7 Image Assessment System (IAS), part of the Landsat-7 Ground System, will calibrate and evaluate the radiometric and geometric performance of the Enhanced Thematic Mapper Plus (ETM +) instrument. The IAS incorporates new instrument radiometric artifact correction and absolute radiometric calibration techniques which overcome some limitations to calibration accuracy inherent in historical calibration methods. Knowledge of ETM + instrument characteristics gleaned from analysis of archival Thematic Mapper in-flight data and from ETM + prelaunch tests allow the determination and quantification of the sources of instrument artifacts. This a priori knowledge will be utilized in IAS algorithms designed to minimize the effects of the noise sources before calibration, in both ETM + image and calibration data.
Implementation of a Relay Coordination System for the Mars Network
NASA Technical Reports Server (NTRS)
Allard, Daniel A.
2010-01-01
Mars network relay operations involve the coordination of lander and orbiter teams through long-term and short-term planning, tactical changes and post-pass analysis. Much of this coordination is managed through email traffic and point-to-point file data exchanges. It is often difficult to construct a complete and accurate picture of the relay situation at any given moment, as there is no centralized store of correlated relay data. The Mars Relay Operations Service (MaROS) is being implemented to address the problem of relay coordination for current and next-generation relay missions. The service is provided for the purpose of coordinating communications sessions between landed spacecraft assets and orbiting spacecraft assets at Mars. The service centralizes a set of functions previously distributed across multiple spacecraft operations teams, and as such greatly improves visibility into the end-to-end strategic coordination process. Most of the process revolves around the scheduling of communications sessions between the spacecraft during periods of time when a landed asset on Mars is geometrically visible by an orbiting spacecraft. These "relay" sessions are used to transfer data both to and from the landed asset via the orbiting asset on behalf of Earth-based spacecraft operators. This paper will discuss the relay coordination problem space, overview the architecture and design selected to meet system requirements, and describe the first phase of system implementation
Coordinated design of coding and modulation systems
NASA Technical Reports Server (NTRS)
Massey, J. L.
1976-01-01
Work on partial unit memory codes continued; it was shown that for a given virtual state complexity, the maximum free distance over the class of all convolutional codes is achieved within the class of unit memory codes. The effect of phase-lock loop (PLL) tracking error on coding system performance was studied by using the channel cut-off rate as the measure of quality of a modulation system. Optimum modulation signal sets for a non-white Gaussian channel considered an heuristic selection rule based on a water-filling argument. The use of error correcting codes to perform data compression by the technique of syndrome source coding was researched and a weight-and-error-locations scheme was developed that is closely related to LDSC coding.
Laser measuring system accurately locates point coordinates on photograph
NASA Technical Reports Server (NTRS)
Doede, J. H.; Lindenmeyer, C. W.; Vonderohe, R. H.
1966-01-01
Laser activated ultraprecision ranging apparatus interfaced with a computer determines point coordinates on a photograph. A helium-neon gas CW laser provides collimated light for a null balancing optical system. This system has no mechanical connection between the ranging apparatus and the photograph.
Influenza Virus Surveillance in Coordinated Swine Production Systems, United States.
Kaplan, Bryan S; DeBeauchamp, Jennifer; Stigger-Rosser, Evelyn; Franks, John; Crumpton, Jeri Carol; Turner, Jasmine; Darnell, Daniel; Jeevan, Trushar; Kayali, Ghazi; Harding, Abbey; Webby, Richard J; Lowe, James F
2015-10-01
To clarify the epidemiology of influenza A viruses in coordinated swine production systems to which no animals from outside the system are introduced, we conducted virologic surveillance during September 2012-September 2013. Animal age, geographic location, and farm type were found to affect the prevalence of these viruses. PMID:26402228
Coordinating Board, Texas College and University System, 1977 Annual Report.
ERIC Educational Resources Information Center
Ashworth, Kenneth H.
The annual report of the Coordinating Board, Texas College and University System for the fiscal year ending August 31, 1977 is presented. An overview of Board activities provides information on institutional authorization, higher education budget requests, institutional units in the College and University System, supply-and-demand career…
Coordinate systems for mapping low-altitude trapped particle fluxes
Heynderickx, D.; Lemaire, J.
1996-07-01
The widely used coordinate system ({ital B},{ital L}) has proved very suitable for most of the region covered by the Van Allen belts, but is not very well suited for the low-altitude regions where the Earth{close_quote}s atmosphere interacts with the trapped particle population. Several alternative coordinate systems have been proposed that aim to take into account the steep flux gradients in the region of the upper atmosphere. An overview of these coordinates is presented. The effectiveness of each system is assessed by mapping the proton flux distribution of NASA{close_quote}s AP-8 model. Special attention is given to Hassitt{close_quote}s weighted average of the atmospheric density over the drift shells of trapped particles, which appears very efficient in mapping fluxes for low {ital L} values. {copyright} {ital 1996 American Institute of Physics.}
Using endmembers as a coordinate system in hyperspectral imagery
NASA Astrophysics Data System (ADS)
Gillis, David; Bowles, Jeffrey H.; Winter, Michael E.
2002-11-01
The linear mixing model (LMM) is a well-known and useful method for decomposing spectra in a hyperspectral image into the sum of their constituents, or endmembers. Mathematically, if the spectra are represented as n-dimensional vectors, then the LMM implies that the set of endmembers defines a basis or coordinate system for the set of spectra. Because the endmembers themselves are generally not orthogonal, the geometry (distances, difference angles, etc.) is changed by moving from band space to endmember space. We explore some of the differences between the two coordinate systems, and show in particular that the difference in angle measurements leads to an improved method for subpixel target detection.
Sun, Xi-Ming; Wang, Xue-Fang; Tan, Ying; Wang, Xiao-Liang; Wang, Wei
2016-06-01
This paper provides a design strategy for temperature control of the gas chromatograph. Usually gas chromatograph is modeled by a simple first order system with a time-delay, and a proportion integration (PI) controller is widely used to regulate the output of the gas chromatograph to the desired temperature. As the characteristics of the gas chromatograph varies at the different temperature range, the single-model based PI controller cannot work well when output temperature varies from one range to another. Moreover, the presence of various disturbance will further deteriorate the performance. In order to improve the accuracy of the temperature control, multiple models are used at the different temperature ranges. With a PI controller designed for each model accordingly, a delay-dependent switching control scheme using the dwell time technique is proposed to ensure the absolute exponential stability of the closed loop. Experiment results demonstrate the effectiveness of the proposed switching technique. PMID:26316283
A LEAST ABSOLUTE SHRINKAGE AND SELECTION OPERATOR (LASSO) FOR NONLINEAR SYSTEM IDENTIFICATION
NASA Technical Reports Server (NTRS)
Kukreja, Sunil L.; Lofberg, Johan; Brenner, Martin J.
2006-01-01
Identification of parametric nonlinear models involves estimating unknown parameters and detecting its underlying structure. Structure computation is concerned with selecting a subset of parameters to give a parsimonious description of the system which may afford greater insight into the functionality of the system or a simpler controller design. In this study, a least absolute shrinkage and selection operator (LASSO) technique is investigated for computing efficient model descriptions of nonlinear systems. The LASSO minimises the residual sum of squares by the addition of a 1 penalty term on the parameter vector of the traditional 2 minimisation problem. Its use for structure detection is a natural extension of this constrained minimisation approach to pseudolinear regression problems which produces some model parameters that are exactly zero and, therefore, yields a parsimonious system description. The performance of this LASSO structure detection method was evaluated by using it to estimate the structure of a nonlinear polynomial model. Applicability of the method to more complex systems such as those encountered in aerospace applications was shown by identifying a parsimonious system description of the F/A-18 Active Aeroelastic Wing using flight test data.
Precise Selenodetic Coordinate System on Artificial Light Refers
NASA Astrophysics Data System (ADS)
Bagrov, Alexander; Pichkhadze, Konstantin M.; Sysoev, Valentin
Historically a coordinate system for the Moon was established on the base of telescopic observations from the Earth. As the angular resolution of Earth-to-Space telescopic observations is limited by Earth atmosphere, and is ordinary worse then 1 ang. second, the mean accuracy of selenodetic coordinates is some angular minutes, which corresponds to errors about 900 meters for positions of lunar objects near center of visible lunar disk, and at least twice more when objects are near lunar poles. As there are no Global Positioning System nor any astronomical observation instruments on the Moon, we proposed to use an autonomous light beacon on the Luna-Globe landing module to fix its position on the surface of the moon ant to use it as refer point for fixation of spherical coordinates system for the Moon. The light beacon is designed to be surely visible by orbiting probe TV-camera. As any space probe has its own stars-orientation system, there is not a problem to calculate a set of directions to the beacon and to the referent stars in probe-centered coordinate system during flight over the beacon. Large number of measured angular positions and time of each observation will be enough to calculate both orbital parameters of the probe and selenodetic coordinates of the beacon by methods of geodesy. All this will allow fixing angular coordinates of any feature of lunar surface in one global coordinate system, referred to the beacon. The satellite’s orbit plane contains ever the center mass of main body, so if the beacon will be placed closely to a lunar pole, we shall determine pole point position of the Moon with accuracy tens times better then it is known now. When angular accuracy of self-orientation by stars of the orbital module of Luna-Glob mission will be 6 angular seconds, then being in circular orbit with height of 200 km the on-board TV-camera will allow calculation of the beacon position as well as 6" corresponding to spatial resolution of the camera. It mean
Study on portable optical 3D coordinate measuring system
NASA Astrophysics Data System (ADS)
Ren, Tongqun; Zhu, Jigui; Guo, Yinbiao
2009-05-01
A portable optical 3D coordinate measuring system based on digital Close Range Photogrammetry (CRP) technology and binocular stereo vision theory is researched. Three ultra-red LED with high stability is set on a hand-hold target to provide measuring feature and establish target coordinate system. Ray intersection based field directional calibrating is done for the intersectant binocular measurement system composed of two cameras by a reference ruler. The hand-hold target controlled by Bluetooth wireless communication is free moved to implement contact measurement. The position of ceramic contact ball is pre-calibrated accurately. The coordinates of target feature points are obtained by binocular stereo vision model from the stereo images pair taken by cameras. Combining radius compensation for contact ball and residual error correction, object point can be resolved by transfer of axes using target coordinate system as intermediary. This system is suitable for on-field large-scale measurement because of its excellent portability, high precision, wide measuring volume, great adaptability and satisfying automatization. It is tested that the measuring precision is near to +/-0.1mm/m.
The modeling of portable 3D vision coordinate measuring system
NASA Astrophysics Data System (ADS)
Liu, Shugui; Huang, Fengshan; Peng, Kai
2005-02-01
The portable three-dimensional vision coordinate measuring system, which consists of a light pen, a CCD camera and a laptop computer, can be widely applied in most coordinate measuring fields especially on the industrial spots. On the light pen there are at least three point-shaped light sources (LEDs) acting as the measured control characteristic points and a touch trigger probe with a spherical stylus which is used to contact the point to be measured. The most important character of this system is that three light sources and the probe stylus are aligned in one line with known positions. In building and studying this measuring system, how to construct the system"s mathematical model is the most key problem called perspective of three-collinear-points problem, which is a particular case of perspective of three-points problem (P3P). On the basis of P3P and spatial analytical geometry theory, the system"s mathematical model is established in this paper. What"s more, it is verified that perspective of three-collinear-points problem has a unique solution. And the analytical equations of the measured point"s coordinates are derived by using the system"s mathematical model and the restrict condition that three light sources and the probe stylus are aligned in one line. Finally, the effectiveness of the mathematical model is confirmed by experiments.
Coordination polymer particles as potential drug delivery systems.
Imaz, Inhar; Rubio-Martínez, Marta; García-Fernández, Lorena; García, Francisca; Ruiz-Molina, Daniel; Hernando, Jordi; Puntes, Victor; Maspoch, Daniel
2010-07-14
Micro- and nanoscale coordination polymer particles can be used for encapsulating and delivering drugs. In vitro cancer cell cytotoxicity assays showed that these capsules readily release doxorubicin, which shows anticancer efficacy. The results from this work open up new avenues for metal-organic capsules to be used as potential drug delivery systems. PMID:20485835
MASDynamics: Toward Systemic Modeling of Decentralized Agent Coordination
NASA Astrophysics Data System (ADS)
Sudeikat, Jan; Renz, Wolfgang
Enabling distributed software systems to purposefully self-organize, i.e. to adapt to dynamically changing execution contexts by the collective adjustment of individual components, challenges current development practices. Since the dynamics of self-organizing systems arise from agent coaction, developers cannot directly infer the macroscopic system behavior from established agent design models. This paper plays a part in an ongoing research effort that addresses the provision of self-organizing processes as design elements, i.e. reusable patterns of agent interrelations. We propose a systemic modeling approach and support the application independent description of (inter-) agent coordination patterns by a domain specific language that allows to map interrelations of agent activity to detailed agent design models. This facilitates the separation of decentralized coordination strategies from domain specific agent implementations and enables development teams to treat nature-inspired coordination strategies, which steer self-organizing dynamics, as design concepts. In addition, we show how this modeling conception provides a declarative programming approach by the automated supplementation of conventional developed agent models with non-linear, inter-agent coordination mechanisms.
On representations for joint moments using a joint coordinate system.
O'Reilly, Oliver M; Sena, Mark P; Feeley, Brian T; Lotz, Jeffrey C
2013-11-01
In studies of the biomechanics of joints, the representation of moments using the joint coordinate system has been discussed by several authors. The primary purpose of this technical brief is to emphasize that there are two distinct, albeit related, representations for moment vectors using the joint coordinate system. These distinct representations are illuminated by exploring connections between the Euler and dual Euler bases, the "nonorthogonal projections" presented in a recent paper by Desroches et al. (2010, "Expression of Joint Moment in the Joint Coordinate System," ASME J. Biomech. Eng., 132(11), p. 11450) and seminal works by Grood and Suntay (Grood and Suntay, 1983, "A Joint Coordinate System for the Clinical Description of Three-Dimensional Motions: Application to the Knee," ASME J. Biomech. Eng., 105(2), pp. 136-144) and Fujie et al. (1996, "Forces and Moment in Six-DOF at the Human Knee Joint: Mathematical Description for Control," Journal of Biomechanics, 29(12), pp. 1577-1585) on the knee joint. It is also shown how the representation using the dual Euler basis leads to straightforward definition of joint stiffnesses. PMID:24008987
Coordinating Board, Texas College and University System, 1978 Annual Report.
ERIC Educational Resources Information Center
Ashworth, Kenneth H.
The 1978 annual report of the Coordinating Board of the Texas College and University System is presented. The Board's major accomplishments in 1978 included the development of enrollment projections for the next decade, adoption of faculty workload guidelines, and implementation of a family practice residency program. The contents of the report…
Installation Manual for the Uniterm System of Coordinate Indexing.
ERIC Educational Resources Information Center
Documentation Inc., Washington, DC.
The Uniterm system of coordinate indexing, developed by the Armed Services Technical Information Agency, provides a method for the organization, storage, and retrieval of information. The contents of reports are analyzed, and terms are assigned to the documents. For each term there is a card upon which the accession number of documents assigned…
Designing Coordinated Assessment Systems for IASA Title I.
ERIC Educational Resources Information Center
Roeber, Edward D.
This paper describes an approach that states and local districts might use to develop a coordinated assessment system so that information collected at state and local levels about programs under Title I of the Improving America's Schools Act (IASA) would be complementary and not redundant. The reauthorization of Title I provides a unique…
Coordinated joint motion control system with position error correction
Danko, George L.
2016-04-05
Disclosed are an articulated hydraulic machine supporting, control system and control method for same. The articulated hydraulic machine has an end effector for performing useful work. The control system is capable of controlling the end effector for automated movement along a preselected trajectory. The control system has a position error correction system to correct discrepancies between an actual end effector trajectory and a desired end effector trajectory. The correction system can employ one or more absolute position signals provided by one or more acceleration sensors supported by one or more movable machine elements. Good trajectory positioning and repeatability can be obtained. A two joystick controller system is enabled, which can in some cases facilitate the operator's task and enhance their work quality and productivity.
Coordinated joint motion control system with position error correction
Danko, George
2011-11-22
Disclosed are an articulated hydraulic machine supporting, control system and control method for same. The articulated hydraulic machine has an end effector for performing useful work. The control system is capable of controlling the end effector for automated movement along a preselected trajectory. The control system has a position error correction system to correct discrepancies between an actual end effector trajectory and a desired end effector trajectory. The correction system can employ one or more absolute position signals provided by one or more acceleration sensors supported by one or more movable machine elements. Good trajectory positioning and repeatability can be obtained. A two-joystick controller system is enabled, which can in some cases facilitate the operator's task and enhance their work quality and productivity.
Coordinate Reference System Metadata in Interdisciplinary Environmental Modeling
NASA Astrophysics Data System (ADS)
Blodgett, D. L.; Arctur, D. K.; Hnilo, J.; Danko, D. M.; Rutledge, G. K.
2011-12-01
For global climate modeling based on a unit sphere, the positional accuracy of transformations between "real earth" coordinates and the spherical earth coordinates is practically irrelevant due to the coarse grid and precision of global models. Consequently, many climate models are driven by data using real-earth coordinates without transforming them to the shape of the model grid. Additionally, metadata to describe the earth shape and its relationship to latitude longitude demarcations, or datum, used for model output is often left unspecified or ambiguous. Studies of weather and climate effects on coastal zones, water resources, agriculture, biodiversity, and other critical domains typically require positional accuracy on the order of several meters or less. This precision requires that a precise datum be used and accounted for in metadata. While it may be understood that climate model results using spherical earth coordinates could not possibly approach this level of accuracy, precise coordinate reference system metadata is nevertheless required by users and applications integrating climate and geographic information. For this reason, data publishers should provide guidance regarding the appropriate datum to assume for their data. Without some guidance, analysts must make assumptions they are uncomfortable or unwilling to make and may spend inordinate amounts of time researching the correct assumption to make. A consequence of the (practically justified for global climate modeling) disregard for datums is that datums are also neglected when publishing regional or local scale climate and weather data where datum information may be important. For example, observed data, like precipitation and temperature measurements, used in downscaling climate model results are georeferenced precisely. If coordinate reference system metadata are disregarded in cases like this, systematic biases in geolocation can result. Additionally, if no datum transformation was applied to
Wittrup, Inge; Burau, Viola
2015-01-01
Introduction Many highly formalised approaches to coordination poorly fit public health and recent studies call for coordination based on complex adaptive systems. Our contribution is two-fold. Empirically, we focus on public health, and theoretically we build on the patient perspective and treat coordination as a process of contingent, two-level negotiations of user needs. Theory and Methods The paper draws on the concept of user needs-based coordination and sees coordination as a process, whereby needs emerging from the life world of the user are made amenable to the health system through negotiations. The analysis is based on an explorative case study of a health promotion initiative in Denmark. It adopts an anthropological qualitative approach and uses a range of qualitative data. Results The analysis identifies four strategies of coordination: the coordinator focusing on the individual user or on relations with other professionals; and the manager coaching the coordinator or providing structural support. Crucially, the coordination strategies by management remain weak as they do not directly relate to specific user needs. Discussion In process of bottom-up negotiations user needs become blurred and this is especially a challenge for management. The study therefore calls for an increased focus on the level nature of negotiations to bridge the gap that currently weakens coordination strategies by management. PMID:26528097
NASA Technical Reports Server (NTRS)
Kumar, D.
1980-01-01
The computer program AFTBDY generates a body fitted curvilinear coordinate system for a wedge curved after body. This wedge curved after body is being used in an experimental program. The coordinate system generated by AFTBDY is used to solve 3D compressible N.S. equations. The coordinate system in the physical plane is a cartesian x,y,z system, whereas, in the transformed plane a rectangular xi, eta, zeta system is used. The coordinate system generated is such that in the transformed plane coordinate spacing in the xi, eta, zeta direction is constant and equal to unity. The physical plane coordinate lines in the different regions are clustered heavily or sparsely depending on the regions where physical quantities to be solved for by the N.S. equations have high or low gradients. The coordinate distribution in the physical plane is such that x stays constant in eta and zeta direction, whereas, z stays constant in xi and eta direction. The desired distribution in x and z is input to the program. Consequently, only the y-coordinate is solved for by the program AFTBDY.
NASA Astrophysics Data System (ADS)
Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin
2016-07-01
A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ∼-28.3 dBm and ∼336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.
NASA Astrophysics Data System (ADS)
Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin
2016-07-01
A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ˜-28.3 dBm and ˜336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.
Reference coordinate systems and frames: Concepts and realization
NASA Astrophysics Data System (ADS)
Mueller, Ivan I.
1985-06-01
Geodynamics has become the subject of intensive international research during the last decade, involving plate tectonics, both on the intra-plate and inter-plate scale, i.e., the study of crustal movements, and the study of earth rotation and of other dynamic phenomena such as the tides. Interrelated are efforts improving our knowledge of the gravity and magnetic fields of the earth. A common requirement for all these investigations is the necessity for a well-defined reference coordinate system (or systems) to which all relevant observations can be referred and in which theories or models for the dynamic behavior of the earth can be formulated. In view of the unprecedented progress in the ability of geodetic observational systems to measure crustal movements and the rotation of the earth, as well as in theory and model development, there is a great need for the theoretical definition, practical realization, and international acceptance of suitable coordinate system(s) to facilitate such work. This article deals with certain aspects of the establishment and maintenance of such a coordinate system.
Dynamic coordination of a self-reconfigurable manipulator system
NASA Technical Reports Server (NTRS)
Kim, Sungbok; Lee, Sukhan
1991-01-01
The authors present the dynamic coordination of a self-reconfigurable manipulator system capable of changing its mechanical structure according to given task requirements. The self-reconfiguration is achieved by reconfiguring the topology of a dual-arm system through serial, parallel, and bracing structures. Particular emphasis is placed on the dynamic coordination of two arms having three different dual-arm topologies. The authors develop the Cartesian space dynamic models of a dual-arm system of three dual-arm topologies and derive the kinematic and dynamic constraints imposed on two arms in cooperation. Dual-arm dynamic manipulabilities are defined to quantify the dynamic performance of three dual-arm topologies in terms of the efficiency of generating Cartesian accelerations. A methodology of selecting serial, parallel, and bracing structures based on dual-arm dynamic manipulabilities is provided.
Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok
2016-01-01
This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293
Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok
2016-01-01
This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293
Galactic coordinate system based on multi-wavelength catalogues
NASA Astrophysics Data System (ADS)
Ding, P.-J.; Liu, J.-C.; Zhu, Z.
2015-08-01
The currently used Galactic Coordinate System (GalCS) is based on the FK5 system at J2000.0, which was transformed from the FK4 system at B1950.0. The limitations and misunderstandings for this transformed GalCS is necessarily be avoided by defining a new GalCS connecting directly to the International Celestial Reference System (ICRS). We try to find the best orientation of the GalCS using data from two all-sky surveys: AKARI and WISE at six wavelengths between 3.4~μm to 90~μm, and synthesize results obtained at various wavelengths to define an improved GalCS in the framework of the ICRS. The revised GalCS parameters for defining the new GalCS in the ICRS are summarized as: α^p = 192°.777, δ^p= 26°.9298, for the equatorial coordinates of the north Galactic pole and θ = 122°.95017 for the position angle of the Galactic center. As one of the Galactic sub-structures, the Galactic warp presents different forms in different GalCS that are constructed with various data and methods, which shows the importance of re-defining a Galactic coordinate system by the IAU for better study of the Galactic structure and kinematics.
Absolute masses and radii determination in multiplanetary systems without stellar models
NASA Astrophysics Data System (ADS)
Almenara, J. M.; Díaz, R. F.; Mardling, R.; Barros, S. C. C.; Damiani, C.; Bruno, G.; Bonfils, X.; Deleuil, M.
2015-11-01
The masses and radii of extrasolar planets are key observables for understanding their interior, formation and evolution. While transit photometry and Doppler spectroscopy are used to measure the radii and masses respectively of planets relative to those of their host star, estimates for the true values of these quantities rely on theoretical models of the host star which are known to suffer from systematic differences with observations. When a system is composed of more than two bodies, extra information is contained in the transit photometry and radial velocity data. Velocity information (finite speed-of-light, Doppler) is needed to break the Newtonian MR-3 degeneracy. We performed a photodynamical modelling of the two-planet transiting system Kepler-117 using all photometric and spectroscopic data available. We demonstrate how absolute masses and radii of single-star planetary systems can be obtained without resorting to stellar models. Limited by the precision of available radial velocities (38 m s-1), we achieve accuracies of 20 per cent in the radii and 70 per cent in the masses, while simulated 1 m s-1 precision radial velocities lower these to 1 per cent for the radii and 2 per cent for the masses. Since transiting multiplanet systems are common, this technique can be used to measure precisely the mass and radius of a large sample of stars and planets. We anticipate these measurements will become common when the TESS and PLATO mission provide high-precision light curves of a large sample of bright stars. These determinations will improve our knowledge about stars and planets, and provide strong constraints on theoretical models.
Absolute reactivity calibration of accelerator-driven systems after RACE-T experiments
Jammes, C. C.; Geslot, B.
2006-07-01
The RACE-T experiments that were held in november 2005 in the ENEA-Casaccia research center near Rome allowed us to improve our knowledge of the experimental techniques for absolute reactivity calibration at either startup or shutdown phases of accelerator-driven systems. Various experimental techniques for assessing a subcritical level were inter-compared through three different subcritical configurations SC0, SC2 and SC3, about -0.5, -3 and -6 dollars, respectively. The area-ratio method based of the use of a pulsed neutron source appears as the most performing. When the reactivity estimate is expressed in dollar unit, the uncertainties obtained with the area-ratio method were less than 1% for any subcritical configuration. The sensitivity to measurement location was about slightly more than 1% and always less than 4%. Finally, it is noteworthy that the source jerk technique using a transient caused by the pulsed neutron source shutdown provides results in good agreement with those obtained from the area-ratio technique. (authors)
Unique sensor fusion system for coordinate-measuring machine tasks
NASA Astrophysics Data System (ADS)
Nashman, Marilyn; Yoshimi, Billibon; Hong, Tsai Hong; Rippey, William G.; Herman, Martin
1997-09-01
This paper describes a real-time hierarchical system that fuses data from vision and touch sensors to improve the performance of a coordinate measuring machine (CMM) used for dimensional inspection tasks. The system consists of sensory processing, world modeling, and task decomposition modules. It uses the strengths of each sensor -- the precision of the CMM scales and the analog touch probe and the global information provided by the low resolution camera -- to improve the speed and flexibility of the inspection task. In the experiment described, the vision module performs all computations in image coordinate space. The part's boundaries are extracted during an initialization process and then the probe's position is continuously updated as it scans and measures the part surface. The system fuses the estimated probe velocity and distance to the part boundary in image coordinates with the estimated velocity and probe position provided by the CMM controller. The fused information provides feedback to the monitor controller as it guides the touch probe to scan the part. We also discuss integrating information from the vision system and the probe to autonomously collect data for 2-D to 3-D calibration, and work to register computer aided design (CAD) models with images of parts in the workplace.
Combined non-contact coordinate measurement system and calibration method
NASA Astrophysics Data System (ADS)
Fan, Yiyan; Zhao, Bin
2015-07-01
A combined non-contact measurement system comprising attitude angle sensor, angle encoder, laser rangefinder, and total station is adopted to measure the spatial coordinate of the hidden zones in large-scale space. The laser from the total station is aimed at the optical system of the attitude angle sensor to obtain the spatial coordinate and the spatial attitude angles. Then, the angle encoder driven by a stepping motor is rotated to drive the laser rangefinder to direct at the measured point. This approach is used to obtain the distance from the rangefinder to the measured point and the angle of the angle encoder. Finally, the spatial coordinates of the measured point can be calculated by using these measured parameters. For the measurement system, we propose a weighted least squares (WLS) calibration method, in which weights are determined for the angular distribution density. Experimental results show that the measurement system could expand the scale and achieve reliable precision during combined measurement and the measurement error of the weighted least squares method is less than that of the ordinary least square (OLS) method.
Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak
2012-08-15
This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 {mu}m) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ('hotspot') was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm{sup 2}/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.
NASA Astrophysics Data System (ADS)
Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak
2012-08-01
This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 μm) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ("hotspot") was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm2/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.
A hierarchical distributed control model for coordinating intelligent systems
NASA Technical Reports Server (NTRS)
Adler, Richard M.
1991-01-01
A hierarchical distributed control (HDC) model for coordinating cooperative problem-solving among intelligent systems is described. The model was implemented using SOCIAL, an innovative object-oriented tool for integrating heterogeneous, distributed software systems. SOCIAL embeds applications in 'wrapper' objects called Agents, which supply predefined capabilities for distributed communication, control, data specification, and translation. The HDC model is realized in SOCIAL as a 'Manager'Agent that coordinates interactions among application Agents. The HDC Manager: indexes the capabilities of application Agents; routes request messages to suitable server Agents; and stores results in a commonly accessible 'Bulletin-Board'. This centralized control model is illustrated in a fault diagnosis application for launch operations support of the Space Shuttle fleet at NASA, Kennedy Space Center.
Control systems and coordination protocols of the secretory pathway.
Luini, Alberto; Mavelli, Gabriella; Jung, Juan; Cancino, Jorge
2014-01-01
Like other cellular modules, the secretory pathway and the Golgi complex are likely to be supervised by control systems that support homeostasis and optimal functionality under all conditions, including external and internal perturbations. Moreover, the secretory apparatus must be functionally connected with other cellular modules, such as energy metabolism and protein degradation, via specific rules of interaction, or "coordination protocols". These regulatory devices are of fundamental importance for optimal function; however, they are generally "hidden" at steady state. The molecular components and the architecture of the control systems and coordination protocols of the secretory pathway are beginning to emerge through studies based on the use of controlled transport-specific perturbations aimed specifically at the detection and analysis of these internal regulatory devices. PMID:25374666
A Triphasic Sorting System: Coordination Cages in Ionic Liquids.
Grommet, Angela B; Bolliger, Jeanne L; Browne, Colm; Nitschke, Jonathan R
2015-12-01
Host-guest chemistry is usually carried out in either water or organic solvents. To investigate the utility of alternative solvents, three different coordination cages were dissolved in neat ionic liquids. By using (19) F NMR spectroscopy to monitor the presence of free and bound guest molecules, all three cages were demonstrated to be stable and capable of encapsulating guests in ionic solution. Different cages were found to preferentially dissolve in different phases, allowing for the design of a triphasic sorting system. Within this system, three coordination cages, namely Fe4 L6 2, Fe8 L12 3, and Fe4 L4 4, each segregated into a distinct layer. Upon the addition of a mixture of three different guests, each cage (in each separate layer) selectively bound its preferred guest. PMID:26494225
The oblate spheroidal harmonics under coordinate system rotation and translation
NASA Astrophysics Data System (ADS)
Panou, Georgios
2014-05-01
Several recent studies in geodesy and related sciences make use of oblate spheroidal harmonics. For instance, the Earth's external gravitational potential can be mathematically expanded in an oblate spheroidal harmonic series which converges outside any spheroid enclosing all the masses. In this presentation, we develop the exact relations between the solid oblate spheroidal harmonics in two coordinate systems, related to each other by an arbitrary rotation or translation. We start with the relations which exist between the spherical harmonics in the two coordinate systems. This problem has received considerable attention in the past and equivalent results have been independently derived by several investigators. Then, combining the previous results with the expressions which relate the solid spherical harmonics and the solid spheroidal harmonics, we obtain the relations under consideration. For simplicity, complex notation has been adopted throughout the work. This approach is also suitable and easy to use in the zonal harmonic expansions. The spherical harmonics under coordinate system rotation and translation are obtained as a degenerate case. The above theory can be used in any spheroidal harmonic model. Finally, some simple examples are given, in order to illuminate the mathematical derivations.
Numerical solution of flow problems using body-fitted coordinate systems
NASA Technical Reports Server (NTRS)
Thompson, J. F.
1980-01-01
The paper deals with numerically generated boundary-fitted coordinate systems. This procedure eliminates the shape of the boundaries as a complicating factor and allows the flow about arbitrary boundaries to be treated essentially as easily as that about simple boundaries. The technique of boundary-fitted coordinate systems is based on a method of automatic numerical generation of a general curvilinear coordinate system having a coordinate line coincident with each boundary of a general multiconnected region involving any number of arbitrarily shaped boundaries. Once the curvilinear coordinate system is generated, any partial differential system of interest may be solved on the coordinate system by transforming the equations and solving the resulting system in finite-difference approximation on the rectangular transformed plane. Attention is given to the types of boundary-fitted coordinate systems, coordinate system control, operation of the coordinate codes, solution of partial differential equations, application to free-surface flow, and other applications of interest.
NASA Astrophysics Data System (ADS)
Dykema, J. A.; Hanssen, L. M.; Mekhontsev, S.; Anderson, J.
2012-12-01
The central role of atmospheric radiative feedbacks to understanding and projecting climate change calls for a robust observational system. Recent studies have shown the value of space-based measurements for putting quantitative constraints on a range of radiative feedback processes through a fingerprinting method applied to long-term observational records. More recent work has suggested the value of demonstrably accurate measurements to disentangle model error from observational uncertainties within reanalysis systems, potentially yielding improved representations of feedback processes within just a few years. Both of these methods rely on space-based measurements that can be objectively tested for accuracy on-orbit. A new class of mission has been proposed that incorporates the same type of empirical tests for accuracy as used in the laboratory into a space-based sensor. One example of such a mission is the Climate Absolute Radiance and Refractivity Observatory (CLARREO), a new mission suggested by the 2006 National Research Council Decadal Survey. CLARREO includes three sensor types: thermal infrared, microwave, and reflected shortwave. This paper presents a laboratory demonstration of prototype systems for testing the on-orbit accuracy of a thermal infrared sensor for CLARREO. These systems utilize infrared lasers to provide monochromatic light sources to quantitatively determine the optical properties of materials. These infrared optical properties are major determinants of the on-orbit radiometric performance of a thermal infrared sensor. For this reason, reliable quantitative information (including uncertainty) that tracks any changes in relevant infrared materials over the mission lifetime is essential to objective assessment of instrument accuracy. The practicality of mid-infrared lasers for these applications is due to the availability and continued evolution of compact, high-efficiency Quantum Cascade Lasers (QCLs). These lasers can provide over 100 m
Flexible coordinate measurement system based on robot for industries
NASA Astrophysics Data System (ADS)
Guo, Yin; Yang, Xue-you; Liu, Chang-jie; Ye, Sheng-hua
2010-10-01
The flexible coordinate measurement system based on robot which is applicable to multi-model vehicle is designed to meet the needs of online measurement for current mainstream mixed body-in-white(BIW) production line. The moderate precision, good flexibility and no blind angle are the benefits of this measurement system. According to the measurement system, a monocular structured light vision sensor has been designed, which can measure not only edges, but also planes, apertures and other features. And a effective way to fast on-site calibration of the whole system using the laser tracker has also been proposed, which achieves the unity of various coordinate systems in industrial fields. The experimental results show satisfactory precision of +/-0.30mm of this measurement system, which is sufficient for the needs of online measurement for body-in-white(BIW) in the auto production line. The system achieves real-time detection and monitoring of the whole process of the car body's manufacture, and provides a complete data support in purpose of overcoming the manufacturing error immediately and accurately and improving the manufacturing precision.
NASA Astrophysics Data System (ADS)
Jing, Xingjian; Wang, Yu; Li, Quankun; Sun, Xiuting
2016-09-01
This study presents the analysis and design of a novel sensor system for measuring the absolute vibration displacement of moving platforms based on the concept of quasi-zero-stiffness (QZS). The sensor system is constructed using positive- and negative-stiffness springs, which make it possible to achieve an equivalent QZS and consequently to create a broadband vibration-free point for absolute vibration displacement measurement in moving platforms. Theoretical analysis is conducted for the analysis and design of the influence of structure parameters on system measurement performance. A prototype is designed which can avoid the drawback of instability in existing QZS systems with negative stiffness, and corresponding data-processing software is developed to fulfill time domain measurements. Both the simulation and experimental results verify the effectiveness of this novel sensor system.
NASA Astrophysics Data System (ADS)
Porras-Aguilar, Rosario; Falaggis, Konstantinos
2016-09-01
Structured light illumination is a well-established technology for noncontact 3D surface measurements. A common challenge in those systems is to obtain the absolute surface information using few measurement frames. This work discusses techniques based on the projection of multiple sinusoidal fringe patterns with different fringe period, as well as the projection of intensity discrete Gray Code and grey-level coded patterns. The use of sinusoidal multi-frequency techniques has been since years an on-going area of research, where various algorithms have been developed based on beats, look-up tables, or number-theoretical approaches. This work shows that a related technique, the so-called algebraic reconstruction technique that is borrowed from the area of multi-wavelength interferometry can be used for this purpose. This approach provides a robust analytical solution to the phase-unwrapping problem. However, this work argues that despite these advances, the acquisition of additional phase maps obtained with different fringe periods requires too many measurement frames, and hence is inefficient. Motivated by that, this work proposes a new grey level coding scheme that uses only few measurement frames, overcomes typical defocus errors, and has an error detecting feature. The latter feature makes the need of separate error detecting algorithms obsolete. This so-called closed-loop space filling curve can be implemented with an arbitrary number of N grey-levels enabling to code up to (2N) code-words. The performance of this so-called closed-loop space filling curve is demonstrated using experimental data.
Unified Selenocentric Reference Coordinates Net in the Dynamic System
NASA Astrophysics Data System (ADS)
Nefedyev, Yuri; Petrova, Natalia; Varaksina, Natalia
In this report the task of the making selenocentric inertial reference net is solved. The purpose is making summary reference net by expansion KSC-1162 selenodetic system using 12 cosmic and ground selenodesic catalogues. The prospective analysis of this net was performed. These selenocentric reference catalogue covers full visible and a part of far lunar sides. Modern cosmic technologies need the accurate coordinate - temporal support including reference frame realization, inertial and dynamic system orientation and studying dynamic and geometry celestial bodies. That refers to dynamic and geometric selenocentric lunar parameters. The catalogue based on mission “Apollo” and reference nets of the west lunar hemisphere made by missions “Zond 5”, ”Zond 8” cover small part of the Moon surface. Three ALSEP stations were used to transform “Apollo” topographic coordinates. Transformation mean-square errors are less than 80 meters and measurement’s errors are about 60 meters. On this account positions inaccuracy near and between ALSEP stations are less 150 meters. The offset from place of the location ALSEP enlarges the supposed mistake is more than 300 m and this is a major part of the lunar surface. In solving the problem of high-precision condensation and expansion of fundamental selenocentric net KSC-1162 on the visible side of the Moon and lunar far side were obtained following new results: a) the analysis and investigation of the accuracy of basic net contained in ULCN were carried out; b) the decryption of common objects for coordinate systems which are being explored was executed; c) the extension of the mathematical content package TSC was carried out; d) the development of TSC as an expert system of universal transformation planet's coordinates was carried out; e) the possibility of applying the ARM-approach to the problem TC on common objects, which allows to find optimal parameter estimation and model structure of TC was confirmed; f) the
Evans, J. Chapman, S.
2014-08-14
Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided.
NASA Astrophysics Data System (ADS)
Donnelly, Russell J.; Sheibley, D.; Belloni, M.; Stamper-Kurn, D.; Vinen, W. F.
2006-12-01
Absolute Zero is a two hour PBS special attempting to bring to the general public some of the advances made in 400 years of thermodynamics. It is based on the book “Absolute Zero and the Conquest of Cold” by Tom Shachtman. Absolute Zero will call long-overdue attention to the remarkable strides that have been made in low-temperature physics, a field that has produced 27 Nobel Prizes. It will explore the ongoing interplay between science and technology through historical examples including refrigerators, ice machines, frozen foods, liquid oxygen and nitrogen as well as much colder fluids such as liquid hydrogen and liquid helium. A website has been established to promote the series: www.absolutezerocampaign.org. It contains information on the series, aimed primarily at students at the middle school level. There is a wealth of material here and we hope interested teachers will draw their student’s attention to this website and its substantial contents, which have been carefully vetted for accuracy.
Microgrids and distributed generation systems: Control, operation, coordination and planning
NASA Astrophysics Data System (ADS)
Che, Liang
Distributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are key components in microgrid operations. A microgrid is a small electric power system integrated with on-site DERs to serve all or some portion of the local load and connected to the utility grid through the point of common coupling (PCC). Microgrids can operate in both grid-connected mode and island mode. The structure and components of hierarchical control for a microgrid at Illinois Institute of Technology (IIT) are discussed and analyzed. Case studies would address the reliable and economic operation of IIT microgrid. The simulation results of IIT microgrid operation demonstrate that the hierarchical control and the coordination strategy of distributed energy resources (DERs) is an effective way of optimizing the economic operation and the reliability of microgrids. The benefits and challenges of DC microgrids are addressed with a DC model for the IIT microgrid. We presented the hierarchical control strategy including the primary, secondary, and tertiary controls for economic operation and the resilience of a DC microgrid. The simulation results verify that the proposed coordinated strategy is an effective way of ensuring the resilient response of DC microgrids to emergencies and optimizing their economic operation at steady state. The concept and prototype of a community microgrid that interconnecting multiple microgrids in a community are proposed. Two works are conducted. For the coordination, novel three-level hierarchical coordination strategy to coordinate the optimal power exchanges among neighboring microgrids is proposed. For the planning, a multi-microgrid interconnection planning framework using probabilistic minimal cut-set (MCS) based iterative methodology is proposed for enhancing the economic, resilience, and reliability signals in multi-microgrid operations. The implementation of high-reliability microgrids
Surface-based determination of the pelvic coordinate system
NASA Astrophysics Data System (ADS)
Fieten, Lorenz; Eschweiler, Jörg; Heger, Stefan; Kabir, Koroush; Gravius, Sascha; de la Fuente, Matías; Radermacher, Klaus
2009-02-01
In total hip replacement (THR) one technical factor influencing the risk of dislocation is cup orientation. Computer-assisted surgery systems allow for cup navigation in anatomy-based reference frames. The pelvic coordinate system most used for cup navigation in THR is based on the mid-sagittal plane (MSP) and the anterior pelvic plane (APP). From a geometrical point of view, the MSP can be considered as a mirror plane, whereas the APP can be considered as a tangent plane comprising the anterior superior iliac spines (ASIS) and the pubic tubercles. In most systems relying on the pelvic coordinate system, the most anterior points of the ASIS and the pubic tubercles are selected manually. As manual selection of landmark points is a tedious, time-consuming and error-prone task, a surface-based approach for combined MSP and APP computation is presented in this paper: Homologous points defining the MSP and the landmark points defining the APP are selected automatically from surface patches. It is investigated how MSP computation can benefit from APP computation and vice versa, and clinical perspectives of combined MSP and APP computation are discussed. Experimental results on computed tomography data show that the surface-based approach can improve accuracy.
Human Balance System: A Complex Coordination of Central and Peripheral Systems
... 8428 · INFO @ VESTIBULAR . ORG · WWW . VESTIBULAR . ORG The Human Balance System — A Complex Coordination of Central and ... support. 1 A properly functioning balance system allows humans to see clearly while moving, identify orientation with ...
Control systems improvements in a precision coordinate measuring machine
NASA Astrophysics Data System (ADS)
Douglass, S. S.; Babelay, E. F., Jr.; Igou, R. E.; Woodard, L. M.; Green, W. L.
1981-09-01
A conventional, manually driven Moore No. 3 coordinate measuring machine at the Oak Ridge Y-12 Plant is being upgraded to provide a continuous-path numerical control capability and simultaneously serve as a vehicle for testing new machine slide-control concepts. Besides new lead screw drive motors, an NC machine control unit, and a closed-loop servo system, the machine has also been equipped with vibration isolation, air-bearing slideways, and laser interferometric position feedback. The present conventional slide servo system will be replaced with a digital servo system wherein various feedback and compensation techniques can be realized through the use of a high speed, dedicated digital processor. The improvements to data are described with emphasis on identification and compensation of the slide control systems.
Metabolomic insights into system-wide coordination of vertebrate metamorphosis
2014-01-01
Background After completion of embryogenesis, many organisms experience an additional obligatory developmental transition to attain a substantially different juvenile or adult form. During anuran metamorphosis, the aquatic tadpole undergoes drastic morphological changes and remodelling of tissues and organs to become a froglet. Thyroid hormones are required to initiate the process, but the mechanism whereby the many requisite changes are coordinated between organs and tissues is poorly understood. Metabolites are often highly conserved biomolecules between species and are the closest reflection of phenotype. Due to the extensive distribution of blood throughout the organism, examination of the metabolites contained therein provides a system-wide overview of the coordinated changes experienced during metamorphosis. We performed an untargeted metabolomic analysis on serum samples from naturally-metamorphosing Rana catesbeiana from tadpoles to froglets using ultraperformance liquid chromatography coupled to a mass spectrometer. Total and aqueous metabolite extracts were obtained from each serum sample to select for nonpolar and polar metabolites, respectively, and selected metabolites were validated by running authentic compounds. Results The majority of the detected metabolites (74%) showed statistically significant abundance changes (padj < 0.001) between metamorphic stages. We observed extensive remodelling of five core metabolic pathways: arginine and purine/pyrimidine, cysteine/methionine, sphingolipid, and eicosanoid metabolism and the urea cycle, and found evidence for a major role for lipids during this postembryonic process. Metabolites traditionally linked to human disease states were found to have biological linkages to the system-wide changes occuring during the events leading up to overt morphological change. Conclusions To our knowledge, this is the first wide-scale metabolomic study of vertebrate metamorphosis identifying fundamental pathways
Werner, S.C.; Tanaka, K.L.
2011-01-01
For the boundaries of each chronostratigraphic epoch on Mars, we present systematically derived crater-size frequencies based on crater counts of geologic referent surfaces and three proposed " standard" crater size-frequency production distributions as defined by (a) a simple -2 power law, (b) Neukum and Ivanov, (c) Hartmann. In turn, these crater count values are converted to model-absolute ages based on the inferred cratering rate histories. We present a new boundary definition for the Late Hesperian-Early Amazonian transition. Our fitting of crater size-frequency distributions to the chronostratigraphic record of Mars permits the assignment of cumulative counts of craters down to 100. m, 1. km, 2. km, 5. km, and 16. km diameters to martian epochs. Due to differences in the " standard" crater size-frequency production distributions, a generalized crater-density-based definition to the chronostratigraphic system cannot be provided. For the diameter range used for the boundary definitions, the resulting model absolute age fits vary within 1.5% for a given set of production function and chronology model ages. Crater distributions translated to absolute ages utilizing different curve descriptions can result in absolute age differences exceeding 10%. ?? 2011 Elsevier Inc.
NASA Technical Reports Server (NTRS)
Thome, Kurtis; McCorkel, Joel; Hair, Jason; McAndrew, Brendan; Daw, Adrian; Jennings, Donald; Rabin, Douglas
2012-01-01
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission addresses the need to observe high-accuracy, long-term climate change trends and to use decadal change observations as the most critical method to determine the accuracy of climate change. One of the major objectives of CLARREO is to advance the accuracy of SI traceable absolute calibration at infrared and reflected solar wavelengths. This advance is required to reach the on-orbit absolute accuracy required to allow climate change observations to survive data gaps while remaining sufficiently accurate to observe climate change to within the uncertainty of the limit of natural variability. While these capabilities exist at NIST in the laboratory, there is a need to demonstrate that it can move successfully from NIST to NASA and/or instrument vendor capabilities for future spaceborne instruments. The current work describes the test plan for the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. The goal of the CDS is to allow the testing and evaluation of calibration approaches , alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. The end result of efforts with the SOLARIS CDS will be an SI-traceable error budget for reflectance retrieval using solar irradiance as a reference and methods for laboratory-based, absolute calibration suitable for climate-quality data collections. The CLARREO mission addresses the need to observe high-accuracy, long-term climate change trends and advance the accuracy of SI traceable absolute calibration. The current work describes the test plan for the SOLARIS which is the calibration demonstration
Coordinated scheduling for dynamic real-time systems
NASA Technical Reports Server (NTRS)
Natarajan, Swaminathan; Zhao, Wei
1994-01-01
In this project, we addressed issues in coordinated scheduling for dynamic real-time systems. In particular, we concentrated on design and implementation of a new distributed real-time system called R-Shell. The design objective of R-Shell is to provide computing support for space programs that have large, complex, fault-tolerant distributed real-time applications. In R-shell, the approach is based on the concept of scheduling agents, which reside in the application run-time environment, and are customized to provide just those resource management functions which are needed by the specific application. With this approach, we avoid the need for a sophisticated OS which provides a variety of generalized functionality, while still not burdening application programmers with heavy responsibility for resource management. In this report, we discuss the R-Shell approach, summarize the achievement of the project, and describe a preliminary prototype of R-Shell system.
NASA Astrophysics Data System (ADS)
Thome, Kurtis; McCorkel, Joel; McAndrew, Brendan
2013-09-01
A goal of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is to observe highaccuracy, long-term climate change trends over decadal time scales. The key to such a goal is to improving the accuracy of SI traceable absolute calibration across infrared and reflected solar wavelengths allowing climate change to be separated from the limit of natural variability. The advances required to reach on-orbit absolute accuracy to allow climate change observations to survive data gaps exist at NIST in the laboratory, but still need demonstration that the advances can move successfully from to NASA and/or instrument vendor capabilities for spaceborne instruments. The current work describes the radiometric calibration error budget for the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. The goal of the CDS is to allow the testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. The resulting SI-traceable error budget for reflectance retrieval using solar irradiance as a reference and methods for laboratory-based, absolute calibration suitable for climatequality data collections is given. Key components in the error budget are geometry differences between the solar and earth views, knowledge of attenuator behavior when viewing the sun, and sensor behavior such as detector linearity and noise behavior. Methods for demonstrating this error budget are also presented.
NASA Technical Reports Server (NTRS)
Thome, Kurtis; McCorkel, Joel; McAndrew, Brendan
2013-01-01
A goal of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is to observe highaccuracy, long-term climate change trends over decadal time scales. The key to such a goal is to improving the accuracy of SI traceable absolute calibration across infrared and reflected solar wavelengths allowing climate change to be separated from the limit of natural variability. The advances required to reach on-orbit absolute accuracy to allow climate change observations to survive data gaps exist at NIST in the laboratory, but still need demonstration that the advances can move successfully from to NASA and/or instrument vendor capabilities for spaceborne instruments. The current work describes the radiometric calibration error budget for the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. The goal of the CDS is to allow the testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. The resulting SI-traceable error budget for reflectance retrieval using solar irradiance as a reference and methods for laboratory-based, absolute calibration suitable for climatequality data collections is given. Key components in the error budget are geometry differences between the solar and earth views, knowledge of attenuator behavior when viewing the sun, and sensor behavior such as detector linearity and noise behavior. Methods for demonstrating this error budget are also presented.
A system for measuring absolute frequencies of up to 4.25 THz using a Josephson point contact
NASA Astrophysics Data System (ADS)
Mild, Yukinobu; Onae, Atsushi; Kurosawa, Tomizo; Sakuma, Eiichi
1993-11-01
A system for measuring the absolute frequency of a far-infrared (FIR) laser is described. Josephson point contacts have been utilized in the system as a frequency harmonic mixer connecting microwaves and optically pumped CH3OH laser lines. The Josephson point contacts are capable of generating beat signals of 90 GHz microwaves and FIR waves of up to 4.25 THz. To measure the frequency of the beat signals from the Josephson junction with a frequency counter, tracking oscillators have been developed, which tracks the beat signals by phase locking and regenerate clean signals for frequency counting. It is shown that the absolute frequency can be measured to an accuracy of about 100 Hz by using the tracking oscillators.
Spherical Coordinate Systems for Streamlining Suited Mobility Analysis
NASA Technical Reports Server (NTRS)
Benson, Elizabeth; Cowley, Matthew; Harvill, Lauren; Rajulu. Sudhakar
2015-01-01
Introduction: When describing human motion, biomechanists generally report joint angles in terms of Euler angle rotation sequences. However, there are known limitations in using this method to describe complex motions such as the shoulder joint during a baseball pitch. Euler angle notation uses a series of three rotations about an axis where each rotation is dependent upon the preceding rotation. As such, the Euler angles need to be regarded as a set to get accurate angle information. Unfortunately, it is often difficult to visualize and understand these complex motion representations. It has been shown that using a spherical coordinate system allows Anthropometry and Biomechanics Facility (ABF) personnel to increase their ability to transmit important human mobility data to engineers, in a format that is readily understandable and directly translatable to their design efforts. Objectives: The goal of this project was to use innovative analysis and visualization techniques to aid in the examination and comprehension of complex motions. Methods: This project consisted of a series of small sub-projects, meant to validate and verify a new method before it was implemented in the ABF's data analysis practices. A mechanical test rig was built and tracked in 3D using an optical motion capture system. Its position and orientation were reported in both Euler and spherical reference systems. In the second phase of the project, the ABF estimated the error inherent in a spherical coordinate system, and evaluated how this error would vary within the reference frame. This stage also involved expanding a kinematic model of the shoulder to include the rest of the joints of the body. The third stage of the project involved creating visualization methods to assist in interpreting motion in a spherical frame. These visualization methods will be incorporated in a tool to evaluate a database of suited mobility data, which is currently in development. Results: Initial results
NASA Astrophysics Data System (ADS)
Phillips, Alfred, Jr.
Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .
NASA Astrophysics Data System (ADS)
Most, Sebastian; Nowak, Wolfgang; Bijeljic, Branko
2016-04-01
For understanding non-Fickian transport in porous media, thorough understanding of pore-scale processes is required. When using particle methods as research instruments, we need a detailed understanding of the dependence and memory between subsequent increments in particle motion. We are especially interested in the dependence and memory of the spatial increments (size and direction) at consecutive time steps. Understanding the increment statistics is crucial for the upscaling that always becomes essential for transport simulations at larger scales. Upscaling means averaging over a (representative elementary) volume to save limited computational resources. However, this averaging means a loss of detail and therefore dispersion models should compensate for this loss. Formulating an appropriate dispersion model requires a detailed understanding of the dependencies and memory effects in the transport process. Particle-based simulations for transport in porous media are usually conducted and analyzed in a Cartesian coordinate system. We will show that, for understanding the process physically and representing the process statistically, it is more appropriate to switch to a spherical coordinate system that moves with each particle. Increment statistics in a Cartesian coordinate system usually reveal that a large displacement in longitudinal direction triggers a large displacement in transverse direction as fast flow channels are not perfectly aligned with the Cartesian axis along the main flow direction. We can overcome this inherent link, typical for the Cartesian description by using the absolute displacements together with the direction of the particle movement, where the direction is determined by the angles azimuth and elevation. This can be understood as a Lagrangian spherical process description. The root of the dependence of the transport process is in the complex pore geometry. For some time past, high-resolution micro-CT scans of pore space geometry became the
Zhang, J; Zhuang, G; Wang, Z J; Ding, Y H; Zhang, X Q; Tang, Y J
2010-07-01
A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper. PMID:20687724
Conservation equations of gasdynamics in curvilinear coordinate systems
NASA Technical Reports Server (NTRS)
Vinokur, M.
1974-01-01
Description of a new method of writing the conservation equations of gasdynamics in curvilinear coordinates which eliminates undifferentiated terms. It is thus possible to readily apply difference schemes derived for Cartesian coordinates which conserve mass, momentum, and energy in the total flow field. The method is derived for orthogonal coordinates, and then extended to cover the most general class of coordinate transformations, using general tensor analysis. Several special features of the equations are discussed.
NASA Technical Reports Server (NTRS)
Moutsoulas, M. (Editor)
1973-01-01
The proceedings of a colloquium on lunar dynamics and observational coordinate systems are presented. Discussions were held on the establishment of a fundamental reference system and on the lunar ephemerides. Abstracts of the subjects discussed at the meeting are submitted. Some of the topics discussed are: (1) coordinates of the Apollo retroreflectors, (2) determination of lunar baselines, (3) numerical series for the variations of lunar coordinates, (4) fundamental craters for establishing a lunar coordinate system, and (5) composite lunar gravity fields.
System safety based on a coordinated principle-based theme
Cooper, J.A.
1998-08-01
In this paper, the authors demonstrate a logical progression for the identification of assets, threats, vulnerabilities, and protective measures, based on a structured approach that incorporates the results of the previous paper. The authors utilize a logical structure for identifying the constituents of the problem, derive appropriate applicable principles, and demonstrate a technique for incorporating the principles into a coordinated safety theme. They also show how to qualitatively assess such generally non-quantifiable items such as safety-component and safety-system response to severe abnormal environments. An illustrative example is followed step-by-step through to a safety system design approach and a safety assessment approach. The general approach is illustrated here through an example, generally representing a test rocket launch scenario, where the concern is the potential for loss of life.
Systems and Methods of Coordination Control for Robot Manipulation
NASA Technical Reports Server (NTRS)
Chang, Chu-Yin (Inventor); English, James (Inventor); Tardella, Neil (Inventor); Bacon, James (Inventor)
2013-01-01
Disclosed herein are systems and methods for controlling robotic apparatus having several movable elements or segments coupled by joints. At least one of the movable elements can include one or more mobile bases, while the others can form one or more manipulators. One of the movable elements can be treated as an end effector for which a certain motion is desired. The end effector may include a tool, for example, or represent a robotic hand (or a point thereon), or one or more of the one or more mobile bases. In accordance with the systems and methods disclosed herein, movement of the manipulator and the mobile base can be controlled and coordinated to effect a desired motion for the end effector. In many cases, the motion can include simultaneously moving the manipulator and the mobile base.
Galactic coordinate system based on multi-wavelength catalogs
NASA Astrophysics Data System (ADS)
Ding, Ping-Jie; Zhu, Zi; Liu, Jia-Cheng
2015-07-01
The currently used Galactic coordinate system (GalCS) is based on the FK5 system at J2000.0, which was transformed from the FK4 system at B1950.0. The limitations and misunderstandings related to this transformed GalCS can be avoided by defining a new GalCS that is directly connected to the International Celestial Reference System (ICRS). With more data at various wavelengths released by large survey programs, a more appropriate GalCS consistent with features associated with the Milky Way can be established. We try to find the best orientation of the GalCS using data from two all-sky surveys, AKARI and WISE, at six wavelengths between 3.4 μm and 90 μm, and synthesize results obtained at various wavelengths to define an improved GalCS in the framework of the ICRS. The revised GalCS parameters for defining the new GalCS in the ICRS are summarized as: αp = 192.777°, δp = 26.9298°, for the equatorial coordinates of the north Galactic pole and θ = 122.95017° for the position angle of the Galactic center. As one of the Galactic substructures, the Galactic warp exhibits different forms in different GalCSs that are constructed with various data and methods, which shows the importance of re-defining the GalCS by the relative commission of the International Astronomical Union that can lead to a better understanding of Galactic structure and kinematics. Supported by the National Natural Science Foundation of China.
Absolute Position of Targets Measured Through a Chamber Window Using Lidar Metrology Systems
NASA Technical Reports Server (NTRS)
Kubalak, David; Hadjimichael, Theodore; Ohl, Raymond; Slotwinski, Anthony; Telfer, Randal; Hayden, Joseph
2012-01-01
Lidar is a useful tool for taking metrology measurements without the need for physical contact with the parts under test. Lidar instruments are aimed at a target using azimuth and elevation stages, then focus a beam of coherent, frequency modulated laser energy onto the target, such as the surface of a mechanical structure. Energy from the reflected beam is mixed with an optical reference signal that travels in a fiber path internal to the instrument, and the range to the target is calculated based on the difference in the frequency of the returned and reference signals. In cases when the parts are in extreme environments, additional steps need to be taken to separate the operator and lidar from that environment. A model has been developed that accurately reduces the lidar data to an absolute position and accounts for the three media in the testbed air, fused silica, and vacuum but the approach can be adapted for any environment or material. The accuracy of laser metrology measurements depends upon knowing the parameters of the media through which the measurement beam travels. Under normal conditions, this means knowledge of the temperature, pressure, and humidity of the air in the measurement volume. In the past, chamber windows have been used to separate the measuring device from the extreme environment within the chamber and still permit optical measurement, but, so far, only relative changes have been diagnosed. The ability to make accurate measurements through a window presents a challenge as there are a number of factors to consider. In the case of the lidar, the window will increase the time-of-flight of the laser beam causing a ranging error, and refract the direction of the beam causing angular positioning errors. In addition, differences in pressure, temperature, and humidity on each side of the window will cause slight atmospheric index changes and induce deformation and a refractive index gradient within the window. Also, since the window is a
NASA Technical Reports Server (NTRS)
McCorkel, Joel; Thome, Kurtis; Hair, Jason; McAndrew, Brendan; Jennings, Don; Rabin, Douglas; Daw, Adrian; Lundsford, Allen
2012-01-01
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission key goals include enabling observation of high accuracy long-term climate change trends, use of these observations to test and improve climate forecasts, and calibration of operational and research sensors. The spaceborne instrument suites include a reflected solar spectroradiometer, emitted infrared spectroradiometer, and radio occultation receivers. The requirement for the RS instrument is that derived reflectance must be traceable to Sl standards with an absolute uncertainty of <0.3% and the error budget that achieves this requirement is described in previo1L5 work. This work describes the Solar/Lunar Absolute Reflectance Imaging Spectroradiometer (SOLARIS), a calibration demonstration system for RS instrument, and presents initial calibration and characterization methods and results. SOLARIS is an Offner spectrometer with two separate focal planes each with its own entrance aperture and grating covering spectral ranges of 320-640, 600-2300 nm over a full field-of-view of 10 degrees with 0.27 milliradian sampling. Results from laboratory measurements including use of integrating spheres, transfer radiometers and spectral standards combined with field-based solar and lunar acquisitions are presented. These results will be used to assess the accuracy and repeatability of the radiometric and spectral characteristics of SOLARIS, which will be presented against the sensor-level requirements addressed in the CLARREO RS instrument error budget.
Efficient transformations from geodetic to UTM coordinate systems
Toms, R.M.
1996-08-07
The problem of efficiently performing transformations from geocentric to geodetic coordinates has been addressed at previous DIS (Distributed Interactive Simulation) workshops. This paper extends the work presented at the 14th DIS Workshop. As a consequence of the new algorithm for geocentric to geodetic coordinate conversion, a subsequent conversion to Universal Transverse Mercator coordinates is made considerably more efficient. No additional trigonometric or square root evaluations are required and accuracy is not degraded.
Spherical Coordinate Systems for Streamlining Suited Mobility Analysis
NASA Technical Reports Server (NTRS)
Benson, Elizabeth; Cowley, Matthew S.; Harvill. Lauren; Rajulu, Sudhakar
2014-01-01
When describing human motion, biomechanists generally report joint angles in terms of Euler angle rotation sequences. However, there are known limitations in using this method to describe complex motions such as the shoulder joint during a baseball pitch. Euler angle notation uses a series of three rotations about an axis where each rotation is dependent upon the preceding rotation. As such, the Euler angles need to be regarded as a set to get accurate angle information. Unfortunately, it is often difficult to visualize and understand these complex motion representations. One of our key functions is to help design engineers understand how a human will perform with new designs and all too often traditional use of Euler rotations becomes as much of a hindrance as a help. It is believed that using a spherical coordinate system will allow ABF personnel to more quickly and easily transmit important mobility data to engineers, in a format that is readily understandable and directly translatable to their design efforts. Objectives: The goal of this project is to establish new analysis and visualization techniques to aid in the examination and comprehension of complex motions. Methods: This project consisted of a series of small sub-projects, meant to validate and verify the method before it was implemented in the ABF's data analysis practices. The first stage was a proof of concept, where a mechanical test rig was built and instrumented with an inclinometer, so that its angle from horizontal was known. The test rig was tracked in 3D using an optical motion capture system, and its position and orientation were reported in both Euler and spherical reference systems. The rig was meant to simulate flexion/extension, transverse rotation and abduction/adduction of the human shoulder, but without the variability inherent in human motion. In the second phase of the project, the ABF estimated the error inherent in a spherical coordinate system, and evaluated how this error would
A multi-agent system for coordinating international shipping
Goldsmith, S.Y.; Phillips, L.R.; Spires, S.V.
1998-05-01
Moving commercial cargo across the US-Mexico border is currently a complex, paper-based, error-prone process that incurs expensive inspections and delays at several ports of entry in the Southwestern US. Improved information handling will dramatically reduce border dwell time, variation in delivery time, and inventories, and will give better control of the shipment process. The Border Trade Facilitation System (BTFS) is an agent-based collaborative work environment that assists geographically distributed commercial and government users with transshipment of goods across the US-Mexico border. Software agents mediate the creation, validation and secure sharing of shipment information and regulatory documentation over the Internet, using the World Wide Web to interface with human actors. Agents are organized into Agencies. Each agency represents a commercial or government agency. Agents perform four specific functions on behalf of their user organizations: (1) agents with domain knowledge elicit commercial and regulatory information from human specialists through forms presented via web browsers; (2) agents mediate information from forms with diverse otologies, copying invariant data from one form to another thereby eliminating the need for duplicate data entry; (3) cohorts of distributed agents coordinate the work flow among the various information providers and they monitor overall progress of the documentation and the location of the shipment to ensure that all regulatory requirements are met prior to arrival at the border; (4) agents provide status information to human actors and attempt to influence them when problems are predicted.
Some notions of decentralization and coordination in large-scale dynamic systems
NASA Technical Reports Server (NTRS)
Chong, C. Y.
1975-01-01
Some notions of decentralization and coordination in the control of large-scale dynamic systems are discussed. Decentralization and coordination have always been important concepts in the study of large systems. Roughly speaking decentralization is the process of dividing a large problem into subproblems so that it can be handled more easily. Coordination is the manipulation of the subproblem so that the original problem is solved. The various types of decentralization and coordination that have been used to control dynamic systems are discussed. The emphasis was to distinguish between on-line and off-line operations to understand the results available by indicating the aspects of the problem which are decentralized.
A second-order method for interface reconstruction in orthogonal coordinate systems
Colella, P.; Graves, D.T.; Greenough, J.A.
2002-01-02
The authors present a second-order algorithm for reconstructing an interface from a distribution of volume fractions in a general orthogonal coordinate system with derivatives approximated using finite differences. The method approximates the interface curve by a piecewise-linear profile. An integral formulation is used that accounts for the orthogonal coordinate system in a natural way. The authors present results obtained using this method for tracking a material interface between two compressible media in spherical coordinates.
A vision-aided alignment datum system for coordinate measuring machines
NASA Astrophysics Data System (ADS)
Wang, L.; Lin, G. C. I.
1997-07-01
This paper presents the development of a CAD-based and vision-aided precision measurement system. A new coordinate system alignment technique for coordinate measuring machines (CMMs) is described. This alignment technique involves a machine vision system with CAD-based planning and execution of inspection. The determination method for measuring datums for the coordinate measuring technique, using the AutoCAD development system, is described in more detail. To improve image quality in the machine vision system, a contrast enhancement technique is used on the image background to reduce image noise, and an on-line calibration technique is applied. Some systematic errors may be caused by imperfect geometric features in components during coordinate system alignment. This measurement system approach, with its new measuring coordinate alignment method, can be used for high-precision measurement to overcome such errors.
A general relativistic model for free-fall absolute gravimeters
NASA Astrophysics Data System (ADS)
Tan, Yu-Jie; Shao, Cheng-Gang; Li, Jia; Hu, Zhong-Kun
2016-04-01
Although the relativistic manifestations of gravitational fields in gravimetry were first studied 40 years ago, the relativistic effects combined with free-fall absolute gravimeters have rarely been considered. In light of this, we present a general relativistic model for free-fall absolute gravimeters in a local-Fermi coordinates system, where we focus on effects related to the measuring devices: relativistic transverse Doppler effects, gravitational redshift effects and Earth’s rotation effects. Based on this model, a general relativistic expression of the measured gravity acceleration is obtained.
NASA Technical Reports Server (NTRS)
Brown, W.; Ewen, H.; Haroules, G.
1970-01-01
Radiometric receiver system, which measures noise temperatures in degrees Kelvin, does not require cryogenic noise sources for routine operation. It eliminates radiometer calibration errors associated with RF attenuation measurements. Calibrated noise source is required only for laboratory adjustment and calibration.
36 CFR 9.83 - Coordination of AMRAP activities in National Park System units.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Coordination of AMRAP activities in National Park System units. 9.83 Section 9.83 Parks, Forests, and Public Property NATIONAL PARK... Coordination of AMRAP activities in National Park System units. (a) To facilitate compliance with this...
36 CFR 9.83 - Coordination of AMRAP activities in National Park System units.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Coordination of AMRAP activities in National Park System units. 9.83 Section 9.83 Parks, Forests, and Public Property NATIONAL PARK... Coordination of AMRAP activities in National Park System units. (a) To facilitate compliance with this...
36 CFR 9.83 - Coordination of AMRAP activities in National Park System units.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Coordination of AMRAP activities in National Park System units. 9.83 Section 9.83 Parks, Forests, and Public Property NATIONAL PARK... Coordination of AMRAP activities in National Park System units. (a) To facilitate compliance with this...
36 CFR 9.83 - Coordination of AMRAP activities in National Park System units.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Coordination of AMRAP activities in National Park System units. 9.83 Section 9.83 Parks, Forests, and Public Property NATIONAL PARK... Coordination of AMRAP activities in National Park System units. (a) To facilitate compliance with this...
36 CFR 9.83 - Coordination of AMRAP activities in National Park System units.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Coordination of AMRAP activities in National Park System units. 9.83 Section 9.83 Parks, Forests, and Public Property NATIONAL PARK... Coordination of AMRAP activities in National Park System units. (a) To facilitate compliance with this...
ERIC Educational Resources Information Center
Kingsley, Chris
2012-01-01
This executive summary describes highlights from the report, "Building Management Information Systems to Coordinate Citywide Afterschool Programs: A Toolkit for Cities." City-led efforts to build coordinated systems of afterschool programming are an important strategy for improving the health, safety and academic preparedness of children and…
Natural Systems: MINNEMAST Coordinated Mathematics - Science Series, Unit 29.
ERIC Educational Resources Information Center
Bakke, Jeannette; And Others
This volume is the last in a series of 29 coordinated MINNEMAST units in mathematics and science for kindergarten and the primary grades. Intended for use by third-grade teachers, this unit guide provides a summary and overview of the unit, a list of materials needed, and descriptions of three groups of lessons. The purposes and procedures for…
Ghoufi, Aziz; Malfreyt, Patrice
2006-12-14
The authors report calculations of the intermolecular potential of mean force (PMF) in the case of the host-guest interaction. The host-guest system is defined by a water soluble calixarene and a cation. With an organic cation such as the tetramethylammonium cation, the calixarene forms an insertion complex, whereas with the Lanthane cation, the supramolecular assembly is an outer-sphere complex. The authors apply a modified free energy perturbation method and the force constraint technique to establish the PMF profiles as a function of the separation distance between the host and guest. They use the PMF profile for the calculation of the absolute thermodynamic properties of association that they compare to the experimental values previously determined. They finish by giving some structural features of the insertion and outer-sphere complexes at the Gibbs free energy minimum. PMID:17176145
Absolute calibration method for fast-streaked, fiber optic light collection, spectroscopy systems.
Johnston, Mark D.; Frogget, Brent; Oliver, Bryan Velten; Maron, Yitzhak; Droemer, Darryl W.; Crain, Marlon D.
2010-04-01
This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.
Revised Age Constraints on Absolute Age Limits for Mercury's Kuiperian and Mansurian Systems
NASA Astrophysics Data System (ADS)
Banks, Maria E.; Zhiyong, Xiao; Braden, Sarah E.; Marchi, Simone S.; Barlow, Nadine G.; Chapman, Clark R.; Fassett, Caleb I.
2015-11-01
On the basis of morphologically distinct basin and crater deposits, Mercury’s surface units have been subdivided into five time-stratigraphic systems (youngest to oldest): Kuiperian, Mansurian, Calorian, Tolstojan, and pre-Tolstojan. Approximate age limits were initially suggested for these systems on the basis of the lunar-derived impact-flux history. High-resolution and multi-band image data obtained by the MErcury Surface, Space ENviroment, GEochemistry, and Ranging (MESSENGER) spacecraft were used to catalogue fresh impact craters interpreted to have formed during the Mansurian and Kuiperian systems. Mansurian and Kuiperian craters are characterized as morphologically fresh with crisp morphologies, well-preserved rims, few or no superposed craters, continuous ejecta with radial lineaments, and well-defined secondary craters; Kuiperian craters have bright ray systems while Mansurian craters maintain fresh morphologies but no longer have discernable ray systems.The density of fresh craters in these datasets, along with the recent production and chronology function of Marchi et al. [2009], are used to estimate new limits for the boundaries of the two most recent of Mercury’s systems. Given the effects of strength and other parameters (such as density), we estimate a model age for the population of craters that have formed since the onset of the Mansurian of ~1.9 ±0.3 Gyr. Likewise we estimate a model age for the population of craters that have formed since the onset of the Kuiperian of ~300 ±40 Myr. A particularly good fit for the Mansurian crater size frequency distribution (SFD) was found for the NEO-derived crater distribution. The same is true for the Kuiperian SFD, although the fit is not as robust as for the Mansurian SFD.
Xian, Feng; Zi, Jin; Wang, Quanhui; Lou, Xiaomin; Sun, Haidan; Lin, Liang; Hou, Guixue; Rao, Weiqiao; Yin, Changcheng; Wu, Lin; Li, Shuwei; Liu, Siqi
2016-08-01
Because of its specificity and sensitivity, targeted proteomics using mass spectrometry for multiple reaction monitoring is a powerful tool to detect and quantify pre-selected peptides from a complex background and facilitates the absolute quantification of peptides using isotope-labeled forms as internal standards. How to generate isotope-labeled peptides remains an urgent challenge for accurately quantitative targeted proteomics on a large scale. Herein, we propose that isotope-labeled peptides fused with a quantitative tag could be synthesized through an expression system in vitro, and the homemade peptides could be enriched by magnetic beads with tag-affinity and globally quantified based on the corresponding multiple reaction monitoring signals provided by the fused tag. An Escherichia coli cell-free protein expression system, protein synthesis using recombinant elements, was adopted for the synthesis of isotope-labeled peptides fused with Strep-tag. Through a series of optimizations, we enabled efficient expression of the labeled peptides such that, after Strep-Tactin affinity enrichment, the peptide yield was acceptable in scale for quantification, and the peptides could be completely digested by trypsin to release the Strep-tag for quantification. Moreover, these recombinant peptides could be employed in the same way as synthetic peptides for multiple reaction monitoring applications and are likely more economical and useful in a laboratory for the scale of targeted proteomics. As an application, we synthesized four isotope-labeled glutathione S-transferase (GST) peptides and added them to mouse sera pre-treated with GST affinity resin as internal standards. A quantitative assay of the synthesized GST peptides confirmed the absolute GST quantification in mouse sera to be measurable and reproducible. PMID:27234506
The Frog-Boiling Attack: Limitations of Anomaly Detection for Secure Network Coordinate Systems
NASA Astrophysics Data System (ADS)
Chan-Tin, Eric; Feldman, Daniel; Hopper, Nicholas; Kim, Yongdae
A network coordinate system assigns Euclidean “virtual” coordinates to every node in a network to allow easy estimation of network latency between pairs of nodes that have never contacted each other. These systems have been implemented in a variety of applications, most notably the popular Azureus/Vuze BitTorrent client. Zage and Nita-Rotaru (CCS 2007) and independently, Kaafar et al. (SIGCOMM 2007), demonstrated that several widely-cited network coordinate systems are prone to simple attacks, and proposed mechanisms to defeat these attacks using outlier detection to filter out adversarial inputs. We propose a new attack, Frog-Boiling, that defeats anomaly-detection based defenses in the context of network coordinate systems, and demonstrate empirically that Frog-Boiling is more disruptive than the previously known attacks. Our results suggest that a new approach is needed to solve this problem: outlier detection alone cannot be used to secure network coordinate systems.
An intelligent hybrid behavior coordination system for an autonomous mobile robot
NASA Astrophysics Data System (ADS)
Luo, Chaomin; Krishnan, Mohan; Paulik, Mark; Fallouh, Samer
2013-12-01
In this paper, development of a low-cost PID controller with an intelligent behavior coordination system for an autonomous mobile robot is described that is equipped with IR sensors, ultrasonic sensors, regulator, and RC filters on the robot platform based on HCS12 microcontroller and embedded systems. A novel hybrid PID controller and behavior coordination system is developed for wall-following navigation and obstacle avoidance of an autonomous mobile robot. Adaptive control used in this robot is a hybrid PID algorithm associated with template and behavior coordination models. Software development contains motor control, behavior coordination intelligent system and sensor fusion. In addition, the module-based programming technique is adopted to improve the efficiency of integrating the hybrid PID and template as well as behavior coordination model algorithms. The hybrid model is developed to synthesize PID control algorithms, template and behavior coordination technique for wall-following navigation with obstacle avoidance systems. The motor control, obstacle avoidance, and wall-following navigation algorithms are developed to propel and steer the autonomous mobile robot. Experiments validate how this PID controller and behavior coordination system directs an autonomous mobile robot to perform wall-following navigation with obstacle avoidance. Hardware configuration and module-based technique are described in this paper. Experimental results demonstrate that the robot is successfully capable of being guided by the hybrid PID controller and behavior coordination system for wall-following navigation with obstacle avoidance.
A Framework for the Relative and Absolute Performance Evaluation of Automated Spectroscopy Systems
NASA Astrophysics Data System (ADS)
Portnoy, David; Heimberg, Peter; Heimberg, Jennifer; Feuerbach, Robert; McQuarrie, Allan; Noonan, William; Mattson, John
2009-12-01
The development of high-speed, high-performance gamma-ray spectroscopy algorithms is critical to the success of many automated threat detection systems. In response to this need a proliferation of such algorithms has taken place. With this proliferation comes the necessary and non-trivial task of validation. There is (and always will be) insufficient experimental data to determine performance of spectroscopy algorithms over the relevant factor space at any reasonable precision. In the case of gamma-ray spectroscopy, there are hundreds of radioisotopes of interest, which may come in arbitrary admixtures, there are many materials of unknown quantity, which may be found in the intervening space between the source and the detection system, and there are also irregular variations in the detector systems themselves. All of these factors and more should be explored to determine algorithm/system performance. This paper describes a statistical framework for the performance estimation and comparison of gamma-ray spectroscopy algorithms. The framework relies heavily on data of increasing levels of artificiality to sufficiently cover the factor space. At each level rigorous statistical methods are employed to validate performance estimates.
A Framework for the Relative and Absolute Performance Evaluation of Automated Spectroscopy Systems
Portnoy, David; Heimberg, Peter; Heimberg, Jennifer; Feuerbach, Robert; McQuarrie, Allan; Noonan, William; Mattson, John
2009-12-02
The development of high-speed, high-performance gamma-ray spectroscopy algorithms is critical to the success of many automated threat detection systems. In response to this need a proliferation of such algorithms has taken place. With this proliferation comes the necessary and non-trivial task of validation. There is (and always will be) insufficient experimental data to determine performance of spectroscopy algorithms over the relevant factor space at any reasonable precision. In the case of gamma-ray spectroscopy, there are hundreds of radioisotopes of interest, which may come in arbitrary admixtures, there are many materials of unknown quantity, which may be found in the intervening space between the source and the detection system, and there are also irregular variations in the detector systems themselves. All of these factors and more should be explored to determine algorithm/system performance. This paper describes a statistical framework for the performance estimation and comparison of gamma-ray spectroscopy algorithms. The framework relies heavily on data of increasing levels of artificiality to sufficiently cover the factor space. At each level rigorous statistical methods are employed to validate performance estimates.
NASA Astrophysics Data System (ADS)
Hoshino, Tasuku
This paper deals with an approximate linearization control of 2-DOF underactuated-by-1 nonlinear systems, proposing a novel linearization coordinate which reduces the approximation error over the state space around the operating point. The coordinate is analytically constructed in a systematic way by solving two first order linear partial differential equations and the solution is given in an infinite series of configuration variables. The resulting linearization feedback is highly nonlinear and the basin of attraction of the stabilized system using proposed coordinate is large, comparing with those of a conventional first order or other lower order linearization coordinates. The approximate linearization control based on the proposed coordinate is applied to the stabilization of a rotational inverted pendulum; the advantage is verified in simulations and experiments. Some perspectives on availability of the linearization coordinate are discussed and they are computed also for a mobile inverted pendulum, Acrobot, and for Pendubot as examples.
NASA Astrophysics Data System (ADS)
Petrova, N.; Nefediev, Yu.; Zagidullin, A.; Kosoulin, V.
2015-10-01
The theory of physical librations is one of traditional field of investigation at the Kazan University. At the present time it is necessary to develop the model of lunar rotation in order to achieve in the theory the accuracy of 0.1 milliseconds of arc, which is the requirement of modern laser ranging observations and other experiments to determine the parameters of the physical libration. Both numerical and analytical approaches are very important, since the first provides greater accuracy, and the second -allows a qualitative analysis of the observed data, revealing features that are sensitive to the different physical phenomena that affect the rotation of the Moon.In particular, the analytical theory has found effective application in computer simulating a new type of observation, such as the ILOM [1], with the purpose to estimate possibilities of the experiment. One of the important application of the libration theory is the developing the selenocentric coordinate system useful for navigation tasks in the near-moon space. Such kind of the system the Union Selenocentric Reference System was constructed at the university on the basis of absolute coordinates of lunar craters, obtained with simultaneous photographing craters and stars.
Zhu, Pengyu; Wang, Chenguang; Huang, Kunlun; Luo, Yunbo; Xu, Wentao
2016-01-01
Digital polymerase chain reaction (PCR) has developed rapidly since it was first reported in the 1990s. However, pretreatments are often required during preparation for digital PCR, which can increase operation error. The single-plex amplification of both the target and reference genes may cause uncertainties due to the different reaction volumes and the matrix effect. In the current study, a quantitative detection system based on the pretreatment-free duplex chamber digital PCR was developed. The dynamic range, limit of quantitation (LOQ), sensitivity and specificity were evaluated taking the GA21 event as the experimental object. Moreover, to determine the factors that may influence the stability of the duplex system, we evaluated whether the pretreatments, the primary and secondary structures of the probes and the SNP effect influence the detection. The results showed that the LOQ was 0.5% and the sensitivity was 0.1%. We also found that genome digestion and single nucleotide polymorphism (SNP) sites affect the detection results, whereas the unspecific hybridization within different probes had little side effect. This indicated that the detection system was suited for both chamber-based and droplet-based digital PCR. In conclusion, we have provided a simple and flexible way of achieving absolute quantitation for genetically modified organism (GMO) genome samples using commercial digital PCR detection systems. PMID:26999129
Zhu, Pengyu; Wang, Chenguang; Huang, Kunlun; Luo, Yunbo; Xu, Wentao
2016-01-01
Digital polymerase chain reaction (PCR) has developed rapidly since it was first reported in the 1990s. However, pretreatments are often required during preparation for digital PCR, which can increase operation error. The single-plex amplification of both the target and reference genes may cause uncertainties due to the different reaction volumes and the matrix effect. In the current study, a quantitative detection system based on the pretreatment-free duplex chamber digital PCR was developed. The dynamic range, limit of quantitation (LOQ), sensitivity and specificity were evaluated taking the GA21 event as the experimental object. Moreover, to determine the factors that may influence the stability of the duplex system, we evaluated whether the pretreatments, the primary and secondary structures of the probes and the SNP effect influence the detection. The results showed that the LOQ was 0.5% and the sensitivity was 0.1%. We also found that genome digestion and single nucleotide polymorphism (SNP) sites affect the detection results, whereas the unspecific hybridization within different probes had little side effect. This indicated that the detection system was suited for both chamber-based and droplet-based digital PCR. In conclusion, we have provided a simple and flexible way of achieving absolute quantitation for genetically modified organism (GMO) genome samples using commercial digital PCR detection systems. PMID:26999129
Electronic Absolute Cartesian Autocollimator
NASA Technical Reports Server (NTRS)
Leviton, Douglas B.
2006-01-01
An electronic absolute Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term absolute in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based absolutely on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic absolute Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the
NASA Astrophysics Data System (ADS)
Greiche, Albert; Biel, Wolfgang; Marchuk, Oleksandr; Burhenn, Rainer
2008-09-01
The new high effiency extreme ultraviolet overview spectrometer (HEXOS) system for the stellarator Wendelstein 7-X is now mounted for testing and adjustment at the tokamak experiment for technology oriented research (TEXTOR). One part of the testing phase was the intensity calibration of the two double spectrometers which in total cover a spectral range from 2.5 to 160.0 nm with overlap. This work presents the current intensity calibration curves for HEXOS and describes the method of calibration. The calibration was implemented with calibrated lines of a hollow cathode light source and the branching ratio technique. The hollow cathode light source provides calibrated lines from 16 up to 147 nm. We could extend the calibrated region in the spectrometers down to 2.8 nm by using the branching line pairs emitted by an uncalibrated pinch extreme ultraviolet light source as well as emission lines from boron and carbon in TEXTOR plasmas. In total HEXOS is calibrated from 2.8 up to 147 nm, which covers most of the observable wavelength region. The approximate density of carbon in the range of the minor radius from 18 to 35 cm in a TEXTOR plasma determined by simulating calibrated vacuum ultraviolet emission lines with a transport code was 5.5×1017 m-3 which corresponds to a local carbon concentration of 2%.
Coordinate-dependent diffusion coefficients: Decay rate in open quantum systems
Sargsyan, V. V.; Palchikov, Yu. V.; Antonenko, N. V.; Kanokov, Z.; Adamian, G. G.
2007-06-15
Based on a master equation for the reduced density matrix of an open quantum collective system, the influence of coordinate-dependent microscopical diffusion coefficients on the decay rate from a metastable state is treated. For various frictions and temperatures larger than a crossover temperature, the quasistationary decay rates obtained with the coordinate-dependent microscopical set of diffusion coefficients are compared with those obtained with the coordinate-independent microscopical set of diffusion coefficients and coordinate-independent and -dependent phenomenological sets of diffusion coefficients. Neglecting the coordinate dependence of diffusion coefficients, one can strongly overestimate or underestimate the decay rate at low temperature. The coordinate-dependent phenomenological diffusion coefficient in momentum are shown to be suitable for applications.
Teaching Absolute Value Meaningfully
ERIC Educational Resources Information Center
Wade, Angela
2012-01-01
What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…
An adaptive control scheme for coordinated multimanipulator systems
Jonghann Jean; Lichen Fu . Dept. of Electrical Engineering)
1993-04-01
The problem of adaptive coordinated control of multiple robot arms transporting an object is addressed. A stable adaptive control scheme for both trajectory tracking and internal force control is presented. Detailed analyses on tracking properties of the object position, velocity and the internal forces exerted on the object are given. It is shown that this control scheme can achieve satisfactory tracking performance without using the measurement of contact forces and their derivatives. It can be shown that this scheme can be realized by decentralized implementation to reduce the computational burden. Moreover, some efficient adaptive control strategies can be incorporated to reduce the computational complexity.
NASA Technical Reports Server (NTRS)
Gnoffo, P. A.
1977-01-01
A generalized curvilinear orthogonal coordinate system is presented which can be used for approximating various axisymmetric and two-dimensional body shapes of interest to aerodynamicists. Such body shapes include spheres, ellipses, spherically capped cones, flat-faced cylinders with rounded corners, circular disks, and planetary probe vehicles. A set of transformation equations is also developed whereby a uniform velocity field approaching a body at any angle of attack can be resolved in the transformed coordinate system. The Navier-Stokes equations are written in terms of a generalized orthogonal coordinate system to show the resultant complexity of the governing equations.
Absolute Antenna Calibration at the US National Geodetic Survey
NASA Astrophysics Data System (ADS)
Mader, G. L.; Bilich, A. L.
2012-12-01
Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. Determination of antenna phase center behavior is known as "antenna calibration". Since 1994, NGS has computed relative antenna calibrations for more than 350 antennas. In recent years, the geodetic community has moved to absolute calibrations - the IGS adopted absolute antenna phase center calibrations in 2006 for use in their orbit and clock products, and NGS's CORS group began using absolute antenna calibration upon the release of the new CORS coordinates in IGS08 epoch 2005.00 and NAD 83(2011,MA11,PA11) epoch 2010.00. Although NGS relative calibrations can be and have been converted to absolute, it is considered best practice to independently measure phase center characteristics in an absolute sense. Consequently, NGS has developed and operates an absolute calibration system. These absolute antenna calibrations accommodate the demand for greater accuracy and for 2-dimensional (elevation and azimuth) parameterization. NGS will continue to provide calibration values via the NGS web site www.ngs.noaa.gov/ANTCAL, and will publish calibrations in the ANTEX format as well as the legacy ANTINFO
NASA Technical Reports Server (NTRS)
Cooper, D. M.
1979-01-01
Electronic transition moments of seven C2 singlet and triplet band systems in the 0.2-1.2 micron spectral region were measured. The measurements were made in emission behind incident shock waves in C2H2-argon mixtures. Narrow bandpass radiometers were used to obtain absolute measurements of shock-excited C2 radiation from which absolute electronic transition moments are derived by a synthetic spectrum analysis. New results are reported for the Ballik-Ramsay, Phillips, Swan, Deslandres-d'Azambuja, Fox-Herzberg, Mulliken, and Freymark systems.
Zhou, Hangyu; Cui, Zhengying; Morita, Shigeru; Fu, Bingzhong; Goto, Motoshi; Sun, Ping; Dong, Chunfeng; Gao, Yadong; Xu, Yuan; Lu, Ping; Yang, Qingwei; Duan, Xuru
2012-10-01
A grazing-incidence flat-field extreme ultraviolet (EUV) spectrometer has been newly developed in HL-2A tokamak. Typical spectral lines are observed from intrinsic impurities of carbon, oxygen, iron, and extrinsic impurity of helium in the wavelength range of 20 Å-500 Å. Bremsstrahlung continuum is measured at different electron densities of HL-2A discharges to calibrate absolute sensitivity of the EUV spectrometer system and to measure effective ionic charge, Z(eff). The sensitivity of a vacuum ultraviolet (VUV) spectrometer system is also absolutely calibrated in overlapped wavelength range of 300 Å-500 Å by comparing the intensity between VUV and EUV line emissions. PMID:23126850
Zhou Hangyu; Cui Zhengying; Fu Bingzhong; Sun Ping; Gao Yadong; Xu Yuan; Lu Ping; Yang Qingwei; Duan Xuru; Morita, Shigeru; Goto, Motoshi; Dong Chunfeng
2012-10-15
A grazing-incidence flat-field extreme ultraviolet (EUV) spectrometer has been newly developed in HL-2A tokamak. Typical spectral lines are observed from intrinsic impurities of carbon, oxygen, iron, and extrinsic impurity of helium in the wavelength range of 20 A-500 A. Bremsstrahlung continuum is measured at different electron densities of HL-2A discharges to calibrate absolute sensitivity of the EUV spectrometer system and to measure effective ionic charge, Z{sub eff}. The sensitivity of a vacuum ultraviolet (VUV) spectrometer system is also absolutely calibrated in overlapped wavelength range of 300 A-500 A by comparing the intensity between VUV and EUV line emissions.
Meirovitch, Hagai
2009-01-01
The commonly used simulation techniques, Metropolis Monte Carlo (MC) and molecular dynamics (MD) are of a dynamical type which enables one to sample system configurations i correctly with the Boltzmann probability, PiB while the value of PiB is not provided directly; therefore, it is difficult to obtain the absolute entropy, S ~ -ln PiB, and the Helmholtz free energy, F. With a different simulation approach developed in polymer physics, a chain is grown step-by-step with transition probabilities (TPs), and thus their product is the value of the construction probability; therefore, the entropy is known. Because all exact simulation methods are equivalent, i.e. they lead to the same averages and fluctuations of physical properties, one can treat an MC or MD sample as if its members have rather been generated step-by-step. Thus, each configuration i of the sample can be reconstructed (from nothing) by calculating the TPs with which it could have been constructed. This idea applies also to bulk systems such as fluids or magnets. This approach has led earlier to the “local states” (LS) and the “hypothetical scanning” (HS) methods, which are approximate in nature. A recent development is the hypothetical scanning Monte Carlo (HSMC) (or molecular dynamics, HSMD) method which is based on stochastic TPs where all interactions are taken into account. In this respect HSMC(D) can be viewed as exact and the only approximation involved is due to insufficient MC(MD) sampling for calculating the TPs. The validity of HSMC has been established by applying it first to liquid argon, TIP3P water, self-avoiding walks, and polyglycine models, where the results for F were found to agree with those obtained by other methods. Subsequently, HSMD was applied to mobile loops of the enzymes porcine pancreatic α-amylase and acetylcholineesterase in explicit water, where the difference of F between the bound and free states of the loop was calculated. Currently HSMD is being extended for
Meirovitch, Hagai
2010-01-01
The commonly used simulation techniques, Metropolis Monte Carlo (MC) and molecular dynamics (MD) are of a dynamical type which enables one to sample system configurations i correctly with the Boltzmann probability, P(i)(B), while the value of P(i)(B) is not provided directly; therefore, it is difficult to obtain the absolute entropy, S approximately -ln P(i)(B), and the Helmholtz free energy, F. With a different simulation approach developed in polymer physics, a chain is grown step-by-step with transition probabilities (TPs), and thus their product is the value of the construction probability; therefore, the entropy is known. Because all exact simulation methods are equivalent, i.e. they lead to the same averages and fluctuations of physical properties, one can treat an MC or MD sample as if its members have rather been generated step-by-step. Thus, each configuration i of the sample can be reconstructed (from nothing) by calculating the TPs with which it could have been constructed. This idea applies also to bulk systems such as fluids or magnets. This approach has led earlier to the "local states" (LS) and the "hypothetical scanning" (HS) methods, which are approximate in nature. A recent development is the hypothetical scanning Monte Carlo (HSMC) (or molecular dynamics, HSMD) method which is based on stochastic TPs where all interactions are taken into account. In this respect, HSMC(D) can be viewed as exact and the only approximation involved is due to insufficient MC(MD) sampling for calculating the TPs. The validity of HSMC has been established by applying it first to liquid argon, TIP3P water, self-avoiding walks (SAW), and polyglycine models, where the results for F were found to agree with those obtained by other methods. Subsequently, HSMD was applied to mobile loops of the enzymes porcine pancreatic alpha-amylase and acetylcholinesterase in explicit water, where the difference in F between the bound and free states of the loop was calculated. Currently
The registration system of the coordinate-tracking setup on the drift chambers
NASA Astrophysics Data System (ADS)
Zadeba, E. A.; Borisov, A. A.; Fakhrutdinov, R. M.; Kokoulin, R. P.; Kompaniets, K. G.; Kozhin, A. S.; Ovechkin, A. S.; Petrukhin, A. A.; Shutenko, V. V.; Yashin, I. I.
2016-02-01
The large-scale coordinate-tracking detector for registration of near-horizontal muon flux generated by ultra-high energy cosmic rays is being developed in MEPhI. Detector is based on the multiwire drift chambers from the neutrino experiment at the IHEP U-70 accelerator. Their key advantages are a large effective area (1.85 m2), good coordinate and angular resolution with a small number of measuring channels. Detector will be operated as a part of the experimental complex NEVOD, in particular, its registration system allows joint operation with Cherenkov water detector (CWD) and coordinate detector DECOR. Coordinate tracking unit on the drift chambers (CTUDC) is mounted on the opposite sides of CWD. It consists of two coordinate planes containing 8 drift chambers and represents a prototype of a full-size setup. Registration system of the CTUDC is based on the E-MISS electronics developed in IHEP, its principle of operation is presented.
Method and apparatus for two-dimensional absolute optical encoding
NASA Technical Reports Server (NTRS)
Leviton, Douglas B. (Inventor)
2004-01-01
This invention presents a two-dimensional absolute optical encoder and a method for determining position of an object in accordance with information from the encoder. The encoder of the present invention comprises a scale having a pattern being predetermined to indicate an absolute location on the scale, means for illuminating the scale, means for forming an image of the pattern; and detector means for outputting signals derived from the portion of the image of the pattern which lies within a field of view of the detector means, the field of view defining an image reference coordinate system, and analyzing means, receiving the signals from the detector means, for determining the absolute location of the object. There are two types of scale patterns presented in this invention: grid type and starfield type.
Hearn, D.J.; Elphinstone, R.D.; Murphree, J.S.; Cogger, L.L. )
1993-02-01
Viking images of the auroral distribution have been used to investigate the relevance of various ionospheric coordinate systems. An important aspect of the large-scale auroral shape is its dependence on the asymmetries of the Earth's internal field. Model predictions of where the aurora occurs, using the equatorial plane's volume current density, agree with observations and imply that the internal field plays a more important role that generally believed. Historically, the belief that the internal field has only small effects seems to stem from the widespread use of the corrected geomagnetic and invariant coordinate systems. These systems involve the mapping of field lines and have advantages in statistical studies and comparisons; less sophisticated systems such as the eccentric dipole coordinate system should be used in individual studies and in studies involving differentiation or integration of some observational parameters. Observations of the auraoral distribution are give to illustrate the universal time, tilt angle, and Kp variability in different coordinate systems and demonstrate that the dominant variability of the aurora is due to internal field asymmetries. A new set of coordinate systems are briefly developed as examples of how to incorporate external field models into studies of auraoral images. It is proposed that the one of these coordinate systems can be used as a test of how well an external field model can match observed auroral distributions. 19 refs., 1 tab.
MAGSAT: Vector magnetometer absolute sensor alignment determination
NASA Technical Reports Server (NTRS)
Acuna, M. H.
1981-01-01
A procedure is described for accurately determining the absolute alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.
Modeling and Simulation of Complex Network Attributes on Coordinating Large Multiagent System
Li, Xiang; Liu, Ming
2014-01-01
With the expansion of distributed multiagent systems, traditional coordination strategy becomes a severe bottleneck when the system scales up to hundreds of agents. The key challenge is that in typical large multiagent systems, sparsely distributed agents can only communicate directly with very few others and the network is typically modeled as an adaptive complex network. In this paper, we present simulation testbed CoordSim built to model the coordination of network centric multiagent systems. Based on the token-based strategy, the coordination can be built as a communication decision problem that agents make decisions to target communications and pass them over to the capable agents who will potentially benefit the team most. We have theoretically analyzed that the characters of complex network make a significant difference with both random and intelligent coordination strategies, which may contribute to future multiagent algorithm design. PMID:24955399
NASA Astrophysics Data System (ADS)
Liu, Dawei; Liu, Kai; Lv, Changchun; Miao, Jungang
2014-01-01
A projective sphere coordinate system in a Wiener filter method to improve the performance of resolution enhancement for microwave radiometer data of a geostationary Earth orbit (GEO) satellite is proposed. Because of the impact of Earth's curvature on remote sensing measurement, the footprint of microwave radiometer is varied while scanning, especially in positions far from subsatellite point. The deconvolution technique used in the microwave radiometer measurements from Earth directly is therefore inaccurate because microwave measurement under this situation cannot be considered as a convolution process. To ameliorate the deconvolution method, a projective spherical coordinate system that enforces the footprint of a microwave radiometer invariant on the surface of a spherical coordinate system in measurements is presented in this article. The performance of the projective coordinate system is evaluated by GEO satellite simulated observations. The simulation results show that the proposed method produces better resolution enhancement, especially in the position where the footprint of the microwave radiometer is seriously influenced by Earth curvature.
The quantization of the radii of coordination spheres cubic crystals and cluster systems
NASA Astrophysics Data System (ADS)
Melnikov, G.; Emelyanov, S.; Ignatenko, N.; Ignatenko, G.
2016-02-01
The article deals with the creation of an algorithm for calculating the radii of coordination spheres and coordination numbers cubic crystal structure and cluster systems in liquids. Solution has important theoretical value since it allows us to calculate the amount of coordination in the interparticle interaction potentials, to predict the processes of growth of the crystal structures and processes of self-organization of particles in the cluster system. One option accounting geometrical and quantum factors is the use of the Fibonacci series to construct a consistent number of focal areas for cubic crystals and cluster formation in the liquid.
Lyons, Renee; Parker, Victoria; Phillips, Stephen
2011-01-01
Objectives: This research project created and evaluated a knowledge-exchange intervention designed to facilitate an increase in organizational readiness for implementing coordinated stroke care in four primarily rural provincial healthcare systems. Intervention: Knowledge brokers were linked to networks within, across and outside the provinces to support, inform and disseminate best practice recommendations for coordinated stroke care within the provincial healthcare systems. Findings: The intervention increased awareness and dissemination of recommendations, which stimulated the implementation of coordinated stroke care. Similar knowledge-exchange interventions might work in other healthcare jurisdictions with similar demographics, to promote evidence-informed improvements in healthcare. PMID:22851988
Eosinophils; Absolute eosinophil count ... the white blood cell count to give the absolute eosinophil count. ... than 500 cells per microliter (cells/mcL). Normal value ranges may vary slightly among different laboratories. Talk ...
An analysis of natural convection film boiling from spheres using the spherical coordinate system
Tso, C.P.; Leong, K.C.; Tan, H.S.
1995-11-01
The problem of natural convection film boiling on a sphere was analyzed by solving the momentum and energy equations in spherical coordinates. These solutions were compared to the analytical model of Frederking and Clark based on the Cartesian coordinate system, empirical correlation of Frederking and Clark and recent experimental data of Tso et al. for boiling in various refrigerants and liquid nitrogen. For the average Nusselt number, good agreement with Frederking and Clark`s model was obtained. Results using spherical coordinates yield a limiting value of 2 for the average Nusselt number near a modified Rayleigh number of 1 which could not be extracted from Frederking and Clark`s model.
Intelligent vehicle electrical power supply system with central coordinated protection
NASA Astrophysics Data System (ADS)
Yang, Diange; Kong, Weiwei; Li, Bing; Lian, Xiaomin
2016-05-01
The current research of vehicle electrical power supply system mainly focuses on electric vehicles (EV) and hybrid electric vehicles (HEV). The vehicle electrical power supply system used in traditional fuel vehicles is rather simple and imperfect; electrical/electronic devices (EEDs) applied in vehicles are usually directly connected with the vehicle's battery. With increasing numbers of EEDs being applied in traditional fuel vehicles, vehicle electrical power supply systems should be optimized and improved so that they can work more safely and more effectively. In this paper, a new vehicle electrical power supply system for traditional fuel vehicles, which accounts for all electrical/electronic devices and complex work conditions, is proposed based on a smart electrical/electronic device (SEED) system. Working as an independent intelligent electrical power supply network, the proposed system is isolated from the electrical control module and communication network, and access to the vehicle system is made through a bus interface. This results in a clean controller power supply with no electromagnetic interference. A new practical battery state of charge (SoC) estimation method is also proposed to achieve more accurate SoC estimation for lead-acid batteries in traditional fuel vehicles so that the intelligent power system can monitor the status of the battery for an over-current state in each power channel. Optimized protection methods are also used to ensure power supply safety. Experiments and tests on a traditional fuel vehicle are performed, and the results reveal that the battery SoC is calculated quickly and sufficiently accurately for battery over-discharge protection. Over-current protection is achieved, and the entire vehicle's power utilization is optimized. For traditional fuel vehicles, the proposed vehicle electrical power supply system is comprehensive and has a unified system architecture, enhancing system reliability and security.
The insulation coordination and surge arrester design for HTS cable system in Icheon substation
NASA Astrophysics Data System (ADS)
Lee, Hansang; Yoon, Dong-Hee; Lee, Seung-Ryul; Yang, Byeong-Mo; Jang, Gilsoo
2013-01-01
This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.
Intelligent multi-agent coordination system for advanced manufacturing
NASA Astrophysics Data System (ADS)
Maturana, Francisco P.; Balasubramanian, Sivaram; Norrie, Douglas H.
1997-12-01
Global competition and rapidly changing customer requirements are forcing major changes in the production styles and configuration of manufacturing organizations. Agent-based systems are showing considerable potential as a new paradigm for agile manufacturing systems. With this approach, centralized and sequential manufacturing planning, scheduling, and control systems may be replaced by distributed intelligent systems to facilitate flexible and rapid response to changing production styles and variations in product requirements. In this paper, the characteristics and components of such a multi-agent architecture for advanced manufacturing are described. This architecture addresses agility in terms of the ability of the manufacturing system to solve manufacturing tasks using virtual enterprise mechanisms while maintaining concurrent information processing and control.
Omar, Mohamed A
2014-01-01
Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations. PMID:25045732
Static Analysis of Large-Scale Multibody System Using Joint Coordinates and Spatial Algebra Operator
Omar, Mohamed A.
2014-01-01
Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations. PMID:25045732
ERIC Educational Resources Information Center
Shaltry, Paul; Kester, Ralph J.
One of a set of twelve documents describing the Career Planning Support System (CPSS) and its use, this guide is designed to help the CPSS coordinator become familiar with CPSS and his or her role. (The Career Planning Support System is a comprehensive guidance program management system which (1) provides techniques to improve a high school's…
Pursit-evasion game analysis in a line of sight coordinate system
NASA Technical Reports Server (NTRS)
Shinar, J.; Davidovitz, A.
1985-01-01
The paper proposes to use line of sight coordinates for the analysis of pursuit-evasion games. The advantage of this method for two-target games is shown to be evident. As a demonstrative example the game of two identical cars is formulated and solved in such coordinate systems. A new type of singular surface, overlooked in a previous study of the same problem, is discovered as a consequence of the simplicity of the solution.
OKADA; BRAVAR, A.; BUNCE, G.; GILL, R.; HUANG, H.; MAKDISI, Y.; NASS, A.; WOOD, J.; ZELENSKI, Z.; ET AL.
2007-09-10
Precise and absolute beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of {Delta}P{sub beam}/P{sub beam} < 5%. The absolute polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip detectors and was installed in the RHIC-ring in 2004. This system features proton-proton elastic scattering in the Coulomb nuclear interference (CNI) region. Precise measurements of the analyzing power A{sub N} of this process has allowed us to achieve {Delta}P{sub beam}/P{sub beam} = 4.2% in 2005 for the first long spin-physics run. In this report, we describe the entire set up and performance of the system. The procedure of beam polarization measurement and analysis results from 2004-2005 are described. Physics topics of AN in the CNI region (four-momentum transfer squared 0.001 < -t < 0.032 (GeV/c){sup 2}) are also discussed. We point out the current issues and expected optimum accuracy in 2006 and the future.
NASA Technical Reports Server (NTRS)
Kumar, D.
1980-01-01
The computer program COORDC generates a body fitted curvilinear coordinate system for corner geometry with or without corner fillets. It is assumed that at any given xi, x remains constant; consequently the only variation is in y and z. It is also assumed that for all xi's in the physical plane the coordinate system in y-z plane is similar. This enables solution of coordinate system for one particular xi = 1 (x for xi = 1 is arbitrarily chosen to be 0.0) and the solution for all other xi plane can be easily specified once the coordinates in the physical plane on the line 1 or = to xi or = to IMAX, eta = 1, zeta = 1 are specified.
Measuring emission coordinates in a pulsar-based relativistic positioning system
NASA Astrophysics Data System (ADS)
Bunandar, Darius; Caveny, Scott A.; Matzner, Richard A.
2011-11-01
A relativistic deep space positioning system has been proposed using four or more pulsars with stable repetition rates. (Each pulsar emits pulses at a fixed repetition period in its rest frame.) The positioning system uses the fact that an event in spacetime can be fully described by emission coordinates: the proper emission time of each pulse measured at the event. The proper emission time of each pulse from four different pulsars—interpolated as necessary—provides the four spacetime coordinates of the reception event in the emission coordinate system. If more than four pulsars are available, the redundancy can improve the accuracy of the determination and/or resolve degeneracies resulting from special geometrical arrangements of the sources and the event. We introduce a robust numerical approach to measure the emission coordinates of an event in any arbitrary spacetime geometry. Our approach uses a continuous solution of the eikonal equation describing the backward null cone from the event. The pulsar proper time at the instant the null cone intersects the pulsar world line is one of the four required coordinates. The process is complete (modulo degeneracies) when four pulsar world lines have been crossed by the light cone. The numerical method is applied in two different examples: measuring emission coordinates of an event in Minkowski spacetime, using pulses from four pulsars stationary in the spacetime; and measuring emission coordinates of an event in Schwarzschild spacetime, using pulses from four pulsars freely falling toward a static black hole. These numerical simulations are merely exploratory, but with improved resolution and computational resources the method can be applied to more pertinent problems. For instance one could measure the emission coordinates, and therefore the trajectory, of the Earth.
Object-Coordinate-Based Bilateral Control System Using Visual Information
NASA Astrophysics Data System (ADS)
Nakajima, Yu; Nozaki, Takahiro; Oyamada, Yuji; Ohnishi, Kouhei
In the field of teleoperation, visual or tactile information obtained by the operators is restricted (e. g., limited or delayed sight) because of communication constraints. Therefore, it is difficult for the operators to operate the system. In this paper, a bilateral control system using the environmental information about the position and posture of a target as obtained by a camera is proposed. The proposed method reduces the workload of the operators by taking some of their tasks. An experiment is conducted to prove the benefit of the proposed method by using a 1-DOF master robot and a 2-DOF slave robot.
Absolute optical instruments without spherical symmetry
NASA Astrophysics Data System (ADS)
Tyc, Tomáš; Dao, H. L.; Danner, Aaron J.
2015-11-01
Until now, the known set of absolute optical instruments has been limited to those containing high levels of symmetry. Here, we demonstrate a method of mathematically constructing refractive index profiles that result in asymmetric absolute optical instruments. The method is based on the analogy between geometrical optics and classical mechanics and employs Lagrangians that separate in Cartesian coordinates. In addition, our method can be used to construct the index profiles of most previously known absolute optical instruments, as well as infinitely many different ones.
System for Inter-Agency Coordination in Adult Education.
ERIC Educational Resources Information Center
King, Gordon A.; Regan, Timothy F.
An innovative system to facilitate inter-agency cooperation in 16 federal agencies concerned with adult basic education is provided. The 16 programs chosen for the study were: (1) Work Incentive Program; (2) Concentrated Employment Program; (3) New Careers; (4) The Cuban Refugee Program; (5) Grants for Community Planning, Services and Training for…
Retinal waves coordinate patterned activity throughout the developing visual system
Ackman, James B.; Burbridge, Timothy J.; Crair, Michael C.
2014-01-01
Summary The morphologic and functional development of the vertebrate nervous system is initially governed by genetic factors and subsequently refined by neuronal activity. However, fundamental features of the nervous system emerge before sensory experience is possible. Thus, activity-dependent development occurring before the onset of experience must be driven by spontaneous activity, but the origin and nature of activity in vivo remains largely untested. Here we use optical methods to demonstrate in live neonatal mice that waves of spontaneous retinal activity are present and propagate throughout the entire visual system before eye opening. This patterned activity encompassed the visual field, relied on cholinergic neurotransmission, preferentially initiated in the binocular retina, and exhibited spatiotemporal correlations between the two hemispheres. Retinal waves were the primary source of activity in the midbrain and primary visual cortex, but only modulated ongoing activity in secondary visual areas. Thus, spontaneous retinal activity is transmitted through the entire visual system and carries patterned information capable of guiding the activity-dependent development of complex intra- and inter- hemispheric circuits before the onset of vision. PMID:23060192
Voluntary coordination as a strategy of plan implementation for health systems agencies.
Berry, D E; Candia, G R
1979-10-01
Health planning agencies are faced with the difficult mission of guiding change within a large complex social system whose power is dispersed. Initial short- and long-range plans have been established as frameworks, and now the major focus is implementation. Regulation (non-voluntary coordination) and voluntary coordination are the major means of implementation. Voluntary coordination is a significant strategy for consideration by Health Systems Agencies (HSAs). It may interact with regulation as a competitor, substitute, or complement. Because of limited regulatory powers, HSAs are dependent upon voluntary coordination as a major means of influencing behavior. Conflict, a major feature of voluntary coordination, has the potential of being used as a constructive means for dialogue; negotiation and bargaining may become positive approaches to arriving at decisions. Legitimized community authority is the primary source of authority in a strategy dominated by voluntary coordination as contrasted to state or federal mandates in a regulatory strategy. Knowledge of the environment within which the HSA operates will assist HSA staff and board to arrive at rational and realistic decisions. PMID:484757
The Lagrangian coordinate system and what it means for two-dimensional crowd flow models
NASA Astrophysics Data System (ADS)
van Wageningen-Kessels, Femke; Leclercq, Ludovic; Daamen, Winnie; Hoogendoorn, Serge P.
2016-02-01
A continuum crowd flow model is solved using the Lagrangian coordinate system. The system has proven to give computational advantages over the traditional Eulerian coordinate system for (one-dimensional) road traffic flow. Our extension of the model and simulation method to (two-dimensional) crowd flow paves the way to explore the advantages for crowd flow simulation. Detailed analysis of the advantages is left for future research. However, this paper provides a first exploration and shows that a model and simulation method for two-dimensional crowd flow can be developed using Lagrangian numerical techniques and that it leads to accurate simulation results.
NASA Technical Reports Server (NTRS)
Shebalin, John V.
1997-01-01
The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.
Franklin, David W.; Flanagan, J. Randall; Wolpert, Daniel M.; Kording, Konrad
2013-01-01
Successful motor performance requires the ability to adapt motor commands to task dynamics. A central question in movement neuroscience is how these dynamics are represented. Although it is widely assumed that dynamics (e.g., force fields) are represented in intrinsic, joint-based coordinates (Shadmehr R, Mussa-Ivaldi FA. J Neurosci 14: 3208–3224, 1994), recent evidence has questioned this proposal. Here we reexamine the representation of dynamics in two experiments. By testing generalization following changes in shoulder, elbow, or wrist configurations, the first experiment tested for extrinsic, intrinsic, or object-centered representations. No single coordinate frame accounted for the pattern of generalization. Rather, generalization patterns were better accounted for by a mixture of representations or by models that assumed local learning and graded, decaying generalization. A second experiment, in which we replicated the design of an influential study that had suggested encoding in intrinsic coordinates (Shadmehr and Mussa-Ivaldi 1994), yielded similar results. That is, we could not find evidence that dynamics are represented in a single coordinate system. Taken together, our experiments suggest that internal models do not employ a single coordinate system when generalizing and may well be represented as a mixture of coordinate systems, as a single system with local learning, or both. PMID:24353296
Research on the multi-angle monocular coordinates measuring system for spatial points
NASA Astrophysics Data System (ADS)
Zhang, Yihui; Sun, Changku; Wang, Peng; Sun, Pengfei
2015-08-01
To improve the accuracy of coordinate measurement, the precise 3D coordinates of spatial points on the surface of the target object are needed. Based on the stereo vision measurement model, an all-around coordinates measuring system with single camera and a two-dimensional turntable is proposed. By controlling the rotation of objects in two different orientations and by the principle of relative motion, the single-CCD sensor model was imaged as a visual multi-CCD sensor model. In other words, the visual CCD sensors at different but relative positions are used to acquire coordinates information of the measured points. Considering the calibration accuracy of those two shafts affecting the accuracy of the entire system, the mathematical calibration model is built, consisting of virtual multi-CCD sensor measuring system based on the non-orthogonal shafting. The shaft and its calibration method are described in detail. The experimental result shows that the system based on the virtual multi-CCD sensor model can achieve the standard deviation of 0.44mm, and thus proves the feasibility of its multi-angle coordinates measurement for spatial points.
A Study of the Coordination of the Higher Adult Education Function Within State Systems.
ERIC Educational Resources Information Center
Parker, Robert
The paper reports the findings of a two-tier data survey involving the chief executive officers of State systems of higher education in determining the extent of their coordination-control of higher adult education. The first general phase of the study indicated that 42 of the 50 systems surveyed had responsibility for higher adult education. In…
47 CFR 25.272 - General inter-system coordination procedures.
Code of Federal Regulations, 2012 CFR
2012-10-01
... network control center which will have the responsibility to monitor space-to-Earth transmissions in its system. This would indirectly monitor uplink earth station transmissions in its system and to coordinate.... (c) The transmitting earth station licensee shall provide the operator(s) of the satellites, on...
47 CFR 25.272 - General inter-system coordination procedures.
Code of Federal Regulations, 2010 CFR
2010-10-01
... network control center which will have the responsibility to monitor space-to-Earth transmissions in its system. This would indirectly monitor uplink earth station transmissions in its system and to coordinate.... (c) The transmitting earth station licensee shall provide the operator(s) of the satellites, on...
47 CFR 25.272 - General inter-system coordination procedures.
Code of Federal Regulations, 2011 CFR
2011-10-01
... network control center which will have the responsibility to monitor space-to-Earth transmissions in its system. This would indirectly monitor uplink earth station transmissions in its system and to coordinate.... (c) The transmitting earth station licensee shall provide the operator(s) of the satellites, on...
AN EVALUATION OF A METHOD FOR IMPROVING SEARCH STRATEGIES IN A COORDINATE SEARCHING SYSTEM.
ERIC Educational Resources Information Center
HEWER, DAVID J.
SEARCH STRATEGIES WHICH CAN BE CONTINUOUSLY MODIFIED WERE DEVELOPED FOR COORDINATE SEARCHING SYSTEMS. USING THE FILES OF THE NASA TECHNOLOGY UTILIZATION PROGRAM AT THE KNOWLEDGE AVAILABILITY SYSTEMS CENTER, UNIVERSITY OF PITTSBURGH, A STUDY WAS CONDUCTED OF THE RETRIEVAL OF RELEVANT DOCUMENTS BY BOTH MANUAL AND MACHINE METHODS FOR FIVE QUESTIONS…
Epigenetic coordination of acute systemic inflammation: potential therapeutic targets
Vachharajani, Vidula; Liu, Tiefu; McCall, Charles E.
2015-01-01
Epigenetic reprogramming of thousands of genes directs the course of acute systemic inflammation, which is highly lethal when dysregulated during sepsis. No molecular-based treatments for sepsis are available. A new concept supports that sepsis is an immunometabolic disease and that loss of control of nuclear epigenetic regulator Sirtuin 1 (SIRT-1), a NAD+ sensor directs immune and metabolic pathways during sepsis. SIRT-1, acting as homeostasis checkpoint, controls hyper and hypo inflammatory responses of sepsis at the microvascular interface, which disseminates inflammatory injury to cause multiple organ failure. Modifying SIRT-1 activity, which can prevent or treat established sepsis in mice, may provide a new way treat sepsis by epigenetically restoring immunometabolic homeostasis. PMID:25088223
A practical coordinate unification method for integrated tactile-optical measuring system
NASA Astrophysics Data System (ADS)
Li, Feng; Peter Longstaff, Andrew; Fletcher, Simon; Myers, Alan
2014-04-01
To meet the requirement of both high speed and high accuracy 3D measurements for dimensional metrology, multi-sensor measuring systems have been developed to measure, analyse and reverse engineer the geometry of objects. This paper presents a new development in coordinate unification called the "centroid of spherical centres" method, which can be used instead of the traditional method which uses three datum-points to perform the geometric transformation and unification of tactile and optical sensors. The benefits of the proposed method are improved accuracy in coordinate unification and the method is used to integrate a coordinate measuring machine (CMM) and optical sensors (structured light scanning system and FaroArm laser line probe). A sphere-plate artefact is developed for data fusion of the multi-sensor system and experimental results validate the accuracy and effectiveness of this method.
NASA Astrophysics Data System (ADS)
Triplett, Benjamin
2008-07-01
The subjects of Multi-vehicle coordinated control and fin-actuated underwater vehicles are receiving significant attention. Coordinated control is becoming more practical as advances in technology increase the areas of application in which systems of multiple vehicles could accomplish challenging tasks that are difficult or infeasible for a single vehicle to complete. Advances in sensor technology, improvements in wireless communication systems, and increases in microprocessor computation speed, all contribute to the creation of successful coordinated control systems. Coordinated target tracking, in which several pursuit autonomous pursuit vehicles follow and maintain state knowledge of a target vehicle, is the coordinated multiple-vehicle problem that is studied in this dissertation. Results show that multiple vehicles can be used to advantage in the target tracking problem, and that the sharing of target state information, whether data from measurements or estimates, improves the target tracking results. A fin-actuated underwater vehicle (FUV) was created as a hardware test platform for the application and study of both geometric methods in control and multiple-vehicle coordination. Combined with simulation based on geometric control methods, the FUV demonstrates remarkably good agreement between theory and experiment. Simple maneuvers such as forward swimming and turning, as well as more complicated agile maneuvers such as snap-turns are demonstrated by the robot and in simulation. Further, the robot is used with feedback control and radio communication in order to accomplish a number of individual and multi-vehicle tasks, such as radio-control, autonomous trajectory tracking, and coordinated heading control.
Atmospheric pressure loading effects on Global Positioning System coordinate determinations
NASA Technical Reports Server (NTRS)
Vandam, Tonie M.; Blewitt, Geoffrey; Heflin, Michael B.
1994-01-01
Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes in atmospheric pressure account for up to 24% of the total variance in the GPS height estimates. The detected loading signals are larger at higher latitudes where pressure variations are greatest; the largest effect is observed at Fairbanks, Alaska (latitude 65 deg), with a signal root mean square (RMS) of 5 mm. Out of 19 continuously operating GPS sites (with a mean of 281 daily solutions per site), 18 show a positive correlation between the GPS vertical estimates and the modeled loading displacements. Accounting for loading reduces the variance of the vertical station positions on 12 of the 19 sites investigated. Removing the modeled pressure loading from GPS determinations of baseline length for baselines longer than 6000 km reduces the variance on 73 of the 117 baselines investigated. The slight increase in variance for some of the sites and baselines is consistent with expected statistical fluctuations. The results from most stations are consistent with approximately 65% of the modeled pressure load being found in the GPS vertical position measurements. Removing an annual signal from both the measured heights and the modeled load time series leaves this value unchanged. The source of the remaining discrepancy between the modeled and observed loading signal may be the result of (1) anisotropic effects in the Earth's loading response, (2) errors in GPS estimates of tropospheric delay, (3) errors in the surface pressure data, or (4) annual signals in the time series of loading and station heights. In addition, we find that using site dependent coefficients, determined by fitting local pressure to the modeled radial displacements, reduces the variance of the measured station heights as well as or better than using the global convolution sum.
Absolute nuclear material assay
Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.
2012-05-15
A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.
Absolute nuclear material assay
Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.
2010-07-13
A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.
Burnett, R.A.; Tzemos, S.; Dietz, L.A.
1993-12-01
Past construction and survey practices have resulted in the use of multiple local coordinate systems for measuring and reporting the horizontal position of wells and other facilities and locations on the Hanford Site. This report describes the development of a coordinate transformation process and algorithm and its application to the conversion of the horizontal coordinates of Hanford site wells from the various local coordinate systems and datums to a single standard coordinate system, the Washington Coordinate system of 1983, South Zone 1991 (WCS83S). The coordinate transformation algorithm, implemented as a computer program called CTRANS, uses standard two-dimensional translation, rotation, and scaling transformation equations and can be applied to any set of horizontal point locations. For each point to be transformed, the coefficients of the transformation equations are calculated locally, using the coordinates of the three nearest registration points (points with known locations in both coordinate systems). The report contains a discussion of efforts to verify and validate both the software and the well location data, a description of the methods used to estimate transformation and registration point accuracy, instructions for using the computer program, and a summary of the Hanford well conversion results for each local coordinate system and datum. Also included are the results of using recent U.S. Army Corps of Engineers survey data to obtain estimated measures of location errors in wells for which the local coordinate data source is undocumented, unverified, and therefore of unknown accuracy.
NASA Astrophysics Data System (ADS)
Lewandowski, W.
In the present state of the art of atomic clocks it is desirable that comparisons of these clocks, located in the time metrology laboratories spread around the world, be at the level of a few nanoseconds of accuracy. At present the sole operational way to provide such performance is through the system of GPS satellites. As GPS is a one-way system this implies that special attention must be given to geometrical errors. In order to achieve nanosecond accuracy, the error due to the ground-antenna coordinates should not exceed 1 ns in the global budget of errors of GPS time transfer. To attain this goal the ground-antenna coordinates must be accurately determined in a common worldwide homogeneous geodetic reference frame with uncertainties of order 30 cm. This paper considers the choice of a global reference frame for accurate GPS time transfer and then reports on a worldwide homogenization of GPS antenna coordinates in the principal timing centres.
De Donato, Cinzia; Sanchez, Federico; Santander, Marcos; Natl.Tech.U., San Rafael; Camin, Daniel; Garcia, Beatriz; Grassi, Valerio; /Milan U. /INFN, Milan
2005-05-01
To accurately reconstruct a shower axis from the Fluorescence Detector data it is essential to establish with high precision the absolute pointing of the telescopes. To d that they calculate the absolute pointing of a telescope using sky background data acquired during regular data taking periods. The method is based on the knowledge of bright star's coordinates that provide a reliable and stable coordinate system. it can be used to check the absolute telescope's pointing and its long-term stability during the whole life of the project, estimated in 20 years. They have analyzed background data taken from January to October 2004 to determine the absolute pointing of the 12 telescopes installed both in Los Leones and Coihueco. The method is based on the determination of the mean-time of the variance signal left by a star traversing a PMT's photocathode which is compared with the mean-time obtained by simulating the track of that star on the same pixel.
Precision absolute positional measurement of laser beams.
Fitzsimons, Ewan D; Bogenstahl, Johanna; Hough, James; Killow, Christian J; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry
2013-04-20
We describe an instrument which, coupled with a suitable coordinate measuring machine, facilitates the absolute measurement within the machine frame of the propagation direction of a millimeter-scale laser beam to an accuracy of around ±4 μm in position and ±20 μrad in angle. PMID:23669658
Columbia River Coordinated Information System (CIS), 1992-1993 Annual Report.
Rowe, Mike; Roger, Phillip B.; O'Connor, Dick
1993-11-01
The purposes of this report are to: (1) describe the project to date; (2) to document the work and accomplishments of the (CIS) project for Fiscal Year 1993; and (3) to provide a glimpse of future project direction. The concept of a Coordinated Information System (CIS) as an approach to meeting the growing needs for regionally standardized anadromous fish information.
24 CFR 576.400 - Area-wide systems coordination requirements.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 24 Housing and Urban Development 3 2012-04-01 2012-04-01 false Area-wide systems coordination requirements. 576.400 Section 576.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN...
NASA Technical Reports Server (NTRS)
Warshay, Marvin; Prokopius, Paul
1996-01-01
Though the fuel cell was invented in 1839, it was not until the early 1960's that the fuel cell power system was developed and used for a real application, for the NASA Space Mission Gemini. Unfortunately, fuel cell power systems did not, as a result, become in widespread use. Nevertheless, a great deal of progress has been made by both government and industry, culminating in many successful fuel cell power system demonstrations. Initially, each government agency and each private organization went its own way. Later, it became evident that coordination among programs was essential. An overview is presented of the current coordinated efforts by government and industry in fuel cells, with a sufficient historical background. The primary barriers to coordination of programs were institutional and differing application requirements. Initially, in the institutional area, it was the energy crisis and the formation of DOE which fostered close working relationships among government, manufacturers, and users. The authors discuss the fuel cell power system programs (of NASA, DOE, DOT, DOC, EPRI, GRI, industry, and universities), including missions and applications, technology advances, and demonstrations. The discussion covers the new Solar Regenerative Fuel Cell (RFC) program which has space, defense, and commercial terrestrial applications, and which is an excellent example of both program coordination and the Clinton Administration's dual-use application policy.
ERIC Educational Resources Information Center
Texas Coll. and Univ. System, Austin. Coordinating Board.
The Coordinating Board of the Texas College and University System's annual report and statistical supplement provide data on a variety of issues. The annual report addresses the following areas: 1982-1983 legislative appropriations; average budgeted faculty salaries for Texas public senior colleges and universities and community junior colleges;…
Warshay, M.; Prokopius, P.
1996-01-01
Though the fuel cell was invented in 1839, it was not until the early 1960`s that the fuel cell power system was developed and used for a real application, for the NASA Space Mission Gemini. Unfortunately, fuel cell power systems did not, as a result, become in widespread use. Nevertheless, a great deal of progress has been made by both government and industry, culminating in many successful fuel cell power system demonstrations. Initially, each government agency and each private organization went its own way. Later, it became evident that coordination among programs was essential. An overview is presented of the current coordinated efforts by government and industry in fuel cells, with a sufficient historical background. The primary barriers to coordination of programs were institutional and differing application requirements. Initially, in the institutional area, it was the energy crisis and the formation of DOE which fostered close working relationships among government, manufacturers, and users. The authors discuss the fuel cell power system programs (of NASA, DOE, DOT, DOC, EPRI, GRI, industry, and universities), including missions and applications, technology advances, and demonstrations. The discussion covers the new Solar Regenerative Fuel Cell (RFC) program which has space, defense, and commercial terrestrial applications, and which is an excellent example of both program coordination and the Clinton Administration`s dual-use application policy.
Infant Vocal-Motor Coordination: Precursor to the Gesture-Speech System?
ERIC Educational Resources Information Center
Iverson, Jana M.; Fagan, Mary K.
2004-01-01
This study was designed to provide a general picture of infant vocal-motor coordination and test predictions generated by Iverson and Thelen's (1999) model of the development of the gesture-speech system. Forty-seven 6- to 9-month-old infants were videotaped with a primary caregiver during rattle and toy play. Results indicated an age-related…